RFR: 1859: Add "tags only" option to MirrorBot

[Erik Joelsson]

On Tue, 28 Mar 2023 09:34:32 GMT, Erik Helin <ehelin at openjdk.org> wrote:

> Hi all,
> 
> please review this patch that adds an option to the `MirrorBot` to mirror only tags from one repository to another. I also added some additional logging to `MirrorBot` and cleaned up the logic a bit for selecting the "mode" (tags, mirror, selected branches) that the `MirrorBot` uses.
> 
> ### Testing
> - [x] Added one additional unit test
> 
> Thanks,
> Erik

Could you expand the `MirrorBotFactory` test to verify the new configuration options? It's also worth pointing out that existing configurations will need to be updated when this change goes live.

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PR Review: https://git.openjdk.org/skara/pull/1493#pullrequestreview-1361050262