feat: add autodiscover enabled feature

[jskrill]

what

• Added repo configuration settings {"autodiscover": {"mode": "enabled|disabled|auto"}}
• This feature allows Atlantis to discover projects which aren't enumerated in the repo configuration even if the repo configuration is given
• This feature also allows disabling autodiscover entirely

why

• The utility of this feature is when a user has many projects in a repo and is generally satisfied with the auto discovery logic but needs custom configuration for a limited subset of projects
• Without this feature, the user would have to list every project in their repo in the config file if even if they only wanted to configure one

tests

• I added unit tests for the feature
• I manually tested the changes in a test repo I set up

references

• closes Define projects in atlantis.yaml and allow undefined projects to auto plan #2708

[nitrocode]

@jskrill if you have time, could you test out this build in your setup?

I don't know if you know this but you can create a PR in your fork to merge your feature branch into your fork's main branch, cut a release e.g. v0.27.0, and a ghcr image will be uploaded in your fork to test with. This would give us more confidence that this is working as expected. That and adding any additional tests.

Thanks again for all your efforts.

[jskrill]

@nitrocode I built ghcr.io/jskrill/atlantis:v0.27.0 if you wanna try it out.

I've been testing all this while with Atlantis deployed to my local k8s cluster (using Tilt to automate the build/deploy cycle).

I've been using a PR in this repo for manual testing: jskrill/terraform-atlantis-test#9

As far as unit tests go, I'm think the ones I've written cover the feature pretty well. Let me know if you want any additional testing evidence/etc.

Thanks.

[X-Guardian]

just a few quote suggestions

[nitrocode]

Thank you!

I'll defer to another maintainer to review and merge.

[lukemassa]

Looks good to me! The buildAllCommandsByCfg function is getting pretty long and hard to read with all its if/elses, but that's a pre-existing condition. I left a few small comments

[jskrill]

Are we good to merge?

[jskrill]

Polite bump on this. Are there any other changes needed?

[jamengual]

@jskrill LGTM Thanks for the contribution

[nitrocode]

Thanks for all your work @jskrill !