Add scheduled task for removing unneeded tags from the cockroach repo

**The Problem**

The https://github.com/cockroachdb/cockroach repo contains a number of types of tags that don't need to live very long but some of them end up sticking around for a long while. Specifically:

- The `custombuild*` tags are only needed to trigger a custom build. Once the build is triggered, they can be removed if more than a day old.
- The `provisional-*` tags were part of a past release process and do not represent released items. They can be removed.
- The `staging-*` tags are part of our current release process and normally get removed as part of the release process. They can be removed if more than a month old (usually if more than a few weeks old).

The tags that represent releases follow these formats and they must be kept: `v*`, `beta-*`, `alpha`, `@cockroacklabs/cluster*`.

**Suggested solution**

Write a GitHub Action workflow scheduled to run daily that removes tags outside the known types of tags we want to keep. The rules for this would be:

- Keep all tags of these formats: `v*`, `beta-*`, `alpha`, `@cockroacklabs/cluster*`.
- Keep `staging-*` tags newer than 2 months and delete the rest
- For all other tags, delete if they are more than 5 days old.

Jira issue: CRDB-24409