feat: add silence_pr_comments on plan and apply

[anryko]

what

A feature to allow silencing atlantis plan and atlantis apply on per repo/project basis. This is useful when running a big Atlantis server pool and/or having big repetitive changes. In those cases it could be preferable to rely on the GitHub status check and disable Atlantis comment responses.

why

I have a distributed Atlantis setup where a single PR change is planned by many isolated instances. In this setup, each of those instances will post a repetitive comment response to the GitHub thread. It would be preferable to have an option to control this behavior.

With this feature, it would be possible to add a server-side repo or atlantis.yaml project level config option of silence_pr_comments: ["plan", "apply"] and prevent Atlantis from posting the comment responses on those commands, while still reporting the status check updates.

tests

• I ensured the existing tests do still work and added some new ones.
• I tested my changes manually in the local test environment.

references

• closes Add an option to disable github plan/apply/policy_check comments for a workflow #4386

[chenrui333]

lgtm

[chenrui333]

@anryko can you pull the latest main and fix the conflicts? Thanks!

[anryko]

@chenrui333 I rebased and retested the feature locally. Some GH checks are failing, but it seems to be a build system issue... Thank you for the review!