Add BuildLog expiration options

Description

Could we add an option to automatically expire gitlab-ci build logs? There already exists options for automatically deleting artefacts, and for deleting a single build log, so perhaps it could be modelled after those?

Ideally I'd like to be able to keep build logs for tagged builds forever, but build logs for branch builds expire after a period of time. [Or perhaps after a period of time after the branch is deleted?].

Another option would be "keep last x pipelines".

Links / references

• Issue #3421 (closed) allows users to manually remove a single build log.
• Issue #27762 (closed) adds a feature to automatically expire artifacts.
• Issue #18039 (moved) - this could provide a partial solution