Add GUI app for decoding input text

This is the initial implementation of a GUI application for decoding
input text containing one or more Safe Links URLs (while leaving
surrounding text intact). This new GUI app is currently named `dslg`
based on the existing `dsl` CLI app's functionality and name (with a
"g" suffix for "gui").

This implementation uses the Fyne toolkit which has different build
requirements than the existing CLI `usl` and `dsl` tools (e.g., CGO).
These new build requirements necessitated changing the associated
Makefile to conditionally apply Fyne toolkit settings just to the GUI
application while excluding existing CLI apps.

The end result continues to be portable CLI apps and a GUI application
with the minimal OS dependencies possible. See the updated README file
for more information.

CHANGES

- add initial GUI app (see description above)
- update Makefile to provide conditional build logic
  - Fyne toolkit requires for GUI app
  - general build requirements for CLI apps
- update README to provide coverage for new GUI app
  - including updated build and runtime requirements
- update .dockerignore file
- swap out single build image for x86 and x64 build images with
  support for compiling Fyne toolkit applications
- update RPM and DEB package configs to bundle new GUI app
- update internal URL matching logic to use prefix based matching
  instead of regex matching
  - the regex matching support does not currently require a space
    delimiting input URLs whereas the prefix matching ignores URL
    patterns not surrounded by whitespace
  - this may be reverted in the future if it proves too limiting
- update GitHub Actions workflows to pass Fyne toolkit OS
  dependency requirements to called workflows

refs GH-225

.dockerignore

@@ -30,6 +30,8 @@ scratch/
 # Ignore one-off binary builds
 /ul
 /usl
+/dsl
+/dslg
 
 # Ignore assets generated by Makefile
 /release_assets

.gitattributes

@@ -18,5 +18,6 @@
 #
 # $ git config --global merge.ours.driver true
 
-dependabot/docker/builds/Dockerfile merge=ours
+dependabot/docker/builds/x86/Dockerfile merge=ours
+dependabot/docker/builds/x64/Dockerfile merge=ours
 dependabot/docker/go/Dockerfile merge=ours

.github/dependabot.yml

@@ -11,10 +11,6 @@
 # Monitor Go module dependency updates
 ######################################################################
 
-######################################################################
-# Monitor Go module dependency updates
-######################################################################
-
 version: 2
 updates:
   - package-ecosystem: "gomod"
@@ -55,10 +51,6 @@ updates:
   # Monitor GitHub Actions dependency updates
   ######################################################################
 
-  ######################################################################
-  # Monitor GitHub Actions dependency updates
-  ######################################################################
-
   - package-ecosystem: "github-actions"
     directory: "/"
     open-pull-requests-limit: 10
@@ -112,6 +104,7 @@ updates:
     labels:
       - "dependencies"
       - "CI"
+      - "todo/release"
     allow:
       - dependency-type: "all"
     commit-message:
@@ -135,6 +128,7 @@ updates:
     labels:
       - "dependencies"
       - "CI"
+      - "todo/release"
     allow:
       - dependency-type: "all"
     commit-message:
@@ -145,7 +139,25 @@ updates:
   ######################################################################
 
   - package-ecosystem: docker
-    directory: "/dependabot/docker/builds"
+    directory: "/dependabot/docker/builds/x86"
+    open-pull-requests-limit: 10
+    target-branch: "master"
+    schedule:
+      interval: "daily"
+      time: "02:00"
+      timezone: "America/Chicago"
+    assignees:
+      - "atc0005"
+    labels:
+      - "dependencies"
+      - "builds"
+    allow:
+      - dependency-type: "all"
+    commit-message:
+      prefix: "Build image"
+
+  - package-ecosystem: docker
+    directory: "/dependabot/docker/builds/x64"
     open-pull-requests-limit: 10
     target-branch: "master"
     schedule:
@@ -163,7 +175,25 @@ updates:
       prefix: "Build image"
 
   - package-ecosystem: docker
-    directory: "/dependabot/docker/builds"
+    directory: "/dependabot/docker/builds/x86"
+    open-pull-requests-limit: 10
+    target-branch: "development"
+    schedule:
+      interval: "daily"
+      time: "02:00"
+      timezone: "America/Chicago"
+    assignees:
+      - "atc0005"
+    labels:
+      - "dependencies"
+      - "builds"
+    allow:
+      - dependency-type: "all"
+    commit-message:
+      prefix: "Build image"
+
+  - package-ecosystem: docker
+    directory: "/dependabot/docker/builds/x64"
     open-pull-requests-limit: 10
     target-branch: "development"
     schedule:

.github/workflows/lint-and-build.yml

@@ -17,8 +17,12 @@ on:
 jobs:
   lint_and_build_using_ci_matrix:
     name: CI matrix
+    with:
+      os-dependencies: "make bsdmainutils gcc gcc-multilib gcc-mingw-w64 xz-utils libgl1-mesa-dev xorg-dev"
     uses: atc0005/shared-project-resources/.github/workflows/lint-and-build-using-ci-matrix.yml@master
 
   lint_and_build_using_makefile:
     name: Makefile
+    with:
+      os-dependencies: "make bsdmainutils gcc gcc-multilib gcc-mingw-w64 xz-utils libgl1-mesa-dev xorg-dev"
     uses: atc0005/shared-project-resources/.github/workflows/lint-and-build-using-make.yml@master

.github/workflows/project-analysis.yml

@@ -21,10 +21,14 @@ jobs:
     # Only run this job on non-push events (e.g., pull requests)
     if: github.event_name != 'push'
     name: Lint
+    with:
+      os-dependencies: "make bsdmainutils gcc gcc-multilib gcc-mingw-w64 xz-utils libgl1-mesa-dev xorg-dev"
     uses: atc0005/shared-project-resources/.github/workflows/lint-project-files.yml@master
 
   vulnerability:
     name: Vulnerability
+    with:
+      os-dependencies: "make bsdmainutils gcc gcc-multilib gcc-mingw-w64 xz-utils libgl1-mesa-dev xorg-dev"
     uses: atc0005/shared-project-resources/.github/workflows/vulnerability-analysis.yml@master
 
   go_mod_validation:

.github/workflows/scheduled-monthly.yml

@@ -18,4 +18,6 @@ on:
 jobs:
   monthly:
     name: Monthly Tasks
+    with:
+      os-dependencies: "make bsdmainutils gcc gcc-multilib gcc-mingw-w64 xz-utils libgl1-mesa-dev xorg-dev"
     uses: atc0005/shared-project-resources/.github/workflows/scheduled-monthly.yml@master

.github/workflows/scheduled-weekly.yml

@@ -18,4 +18,6 @@ on:
 jobs:
   weekly:
     name: Weekly Tasks
+    with:
+      os-dependencies: "make bsdmainutils gcc gcc-multilib gcc-mingw-w64 xz-utils libgl1-mesa-dev xorg-dev"
     uses: atc0005/shared-project-resources/.github/workflows/scheduled-weekly.yml@master

.gitignore

@@ -31,6 +31,7 @@ scratch/
 /ul
 /usl
 /dsl
+/dslg
 
 # Ignore assets generated by Makefile
 /release_assets