Alternative implementation of the deployment-status action.

[smarnach]

This is an alternative implementation of the deployment-status action. It should be backwards-compatible with the existing implementation except it doesn't support the command input and only updates the deployment status.

Advantages:

• Allows setting the deployment_id to identify a pre-existing deployment.
• Allows filtering deployment by sha in addition to ref and environment.
• Sets the log_url for the deployment status to point to the workflow run, so the logs can easily be accessed from the application repo.
• Suitable for running on the self-hosted runners, which don't have Docker installed.
• Eliminates the need to pass in the installation id. It's figured out based on the org of the target repo.
• Scopes the installation token to the targt repo.
• Faster and somewhat simpler than the original implementation.

I'm not sure it's a suitable replacement for all use cases of the old action, and how to migrate to it if that's what you want to do. I would like to be able to use this action for the crash ingestion services, but we could also add it to this repository with a different name.