Update .github templates with latest repolinter configs

[decause-gov]

Now that we have our new repolinter.json configs, we should add them to the .github template repository.

Question: should we have a template for each tier?

[decause-gov]

07/29:
A: No, we're going to standardize on Tier3 instead of having multiple tiers in .github.

• @natalialuzuriaga updated the .github repo to use the new Tier3 templates!
• PR Open. Need to re-add the insert-license-headers.sh files, then we're good to merge!

[decause-gov]

07/29:

• ACTION: update the PR
• GOAL: Merge!

[decause-gov]

08/02:

• Added the license headers script back to it.
• PR is ready for review @decause-gov
• Will close ticket after PR Merged: Update .github repo to Tier 3 Repository Template #4
• QUESTION: Do we add ISSUE_TEMPLATE.md and PULL_REQUEST_TEMPLATE.md to this repo? Isn't there another feature of github now for generating these too? Should we do both? A: yes.
• Goal: Merge the license headers, add our *_TEMPLATE.md files to the repo.

[natalialuzuriaga]

09/05:

• Templates have been added, closing ticket