feat: Consume new -d/--dev Dev Mode command-line flag

[lenny-goodell]

Dev Mode is used when running service locally with the other services running in Docker (aka hybrid mode). This causes all the Host settings pulled from common configuration to be overridden with the value localhost.

If your build fails due to your commit message not passing the build checks, please review the guidelines here: https://github.com/edgexfoundry/app-functions-sdk-go/blob/main/.github/CONTRIBUTING.md

PR Checklist

Please check if your PR fulfills the following requirements:

• I am not introducing a breaking change (if you are, flag in conventional commit message with BREAKING CHANGE: describing the break)
• I am not introducing a new dependency (add notes below if you are)
• I have added unit tests for the new feature or bug fix (if not, why?)
• I have fully tested (add details below) this the new feature or bug fix (if not, why?)
• I have opened a PR for the related docs change (if not, why?)
  feat: Document new -d/--dev command-line flag edgex-docs#1040

Testing Instructions

From latest Compose Builder run make run no-secty ds-virtual
run make build from this branch
run the app template with just -cp flag
Verify the following error

"Unable to get version of Core Metadata: failed to send a http request -> Get \"http://edgex-core-metadata:59881/api/v3/version\": dial tcp: lookup edgex-core-metadata on 8.8.8.8:53: no such host"

run the app template with just -cp -d flags
Verify no errors
Enable DEBUG logging from Consul
Verify service is receiving and processing events

New Dependency Instructions (If applicable)

[codecov-commenter]

Codecov Report

Merging #1397 (a8179ed) into main (fb33968) will not change coverage.
The diff coverage is 0.00%.

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@@           Coverage Diff           @@
##             main    #1397   +/-   ##
=======================================
  Coverage   66.89%   66.89%           
=======================================
  Files          36       36           
  Lines        3057     3057           
=======================================
  Hits         2045     2045           
  Misses        882      882           
  Partials      130      130           

Impacted Files	Coverage Δ
internal/app/service.go	56.36% <0.00%> (ø)