SD 683 - Custom Commit Status URL

[yzdann]

Description

Considerations:

1. Passing command flags instead of CUSTOM_COMMIT_STATUS_URL_TEMPLATE_PATH: the current implementation is more toward using env variable to flags to keep focus on the implementation of this feature we don't do that
2. Reading env variable in commitStatusTargetURL instead of loading it in application startup: the current code doesn't have the flexibility to read the env on start-up and expose as config it to the rest of the application. To change
   that we need to change a couple of functions signature and it goes out of scope for this PR. see here

Read this PR commit by commit, to understand the changes:

Feature:

• Generate target URL with dynamic value (CommitTime)
• Inject /etc/telefonistka-gh-app-config/ for mirrord - will be used for CUSTOM_COMMIT_STATUS_URL_TEMPLATE_PATH
• Add doc
• Add test

Extra Adjustments:

• Return err as second value
• Make executeTemplate more general by extracting template path join

This will be used for CUSTOM_COMMIT_STATUS_URL_TEMPLATE_PATH

Type of Change

• Bug Fix
• New Feature
• Breaking Change
• Refactor
• Documentation
• Other (please describe)

Checklist

• I have read the contributing guidelines
• Existing issues have been referenced (where applicable)
• I have verified this change is not present in other open pull requests
• Functionality is documented
• All code style checks pass
• New code contribution is covered by automated tests
• All new and existing tests pass

[yzdann]

a bit more complicated calculations that we might use:

.CommitTime.Add -600000000000

is equal to:

CommitTime.Add(-10*time.Minute).UnixMilli()