feat: Add support for s3 persistence to log streaming jobs

[Aayyush]

Changes

• Refactor log handler into receiver registry that tracks the active connections for a job and job store that deals with storing the logs for the jobs.

• Add support for persisting log streaming jobs to s3, with the storage backend easily configurable. Other storage backends such as local storage, Google Cloud storage can be easily added by updating the config passed to Atlantis and passing it to the StorageBackend.

• Closes Store plan output in external source such as S3 and post link in the PR comment instead of full output #121

[nishkrishnan]

Can you add some docs for this feature as well?

[jamengual]

Going to close this one since there is no response.
If someone is interested in working on this , please ask to be reopen

[jacob-jameson]

Did anyone ever check this PR's code to see if it actually works? It seems a bit silly to throw away work like this only because it doesn't have documentation.

If this code actually works, surely someone can (maybe me) can just look at the code to add documentation.

[jamengual]

If you are a golang developer and wants to bring back this feature and add an interface to allow for other storage backends to be added ( not just s3) I do not think we will have any issues on reviewing the PR.