chore(ci): enable CircleCI snapshot and doc publishing

[Splaktar]

PR Checklist

Please check that your PR fulfills the following requirements:

• The commit message follows our guidelines
• Tests for the changes have been added or this is not a bug fix / enhancement
• Docs have been added, updated, or were not required

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[ ] Enhancement
[ ] Documentation content changes
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[x] CI related changes
[ ] Infrastructure changes
[ ] Other... Please describe:

What is the current behavior?

CircleCI is not enabled to create snapshots, add tags, or update the docs on commits to master.

Issue Number:
Relates to #11592

What is the new behavior?

After a commit to master, CircleCI runs lint and tests against different AngularJS versions. If those are successful and the commit was to the master branch, then it snapshots, commits to angular/code.material.angularjs.org, and deploys the updated docs site. It also commits and tags the code snapshot in angular/bower-material.

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

The list of tasks related to this and their order can be found in #11592.

Caretaker note: This can't be merged until the GitHub tokens get set up in the CircleCI environment variables as described in #11592.

[Splaktar]

@andrewseguin has set up the GitHub tokens in the CircleCI environment variables as described in #11592.