Some improvement about tags and releases

[lunny]

There's still some things I'm not happy about because of the way gitea handles tags vs. releases. We should follow up and fix:

1. If a tag and a release exists with the same name, the tag list links to the release page with nothing linking to the tag page. Tag list should always link to tags only. Release list links to releases.
2. Tag page is missing both tag title and tag message for "unsynced" tags, showing a rather broken page (as seen above). Idk, ideally fix the sync bug first.

As a first step, gitea should not try to suggest that tags are releases as the current UI does. Those are two distinct concepts that should not be mixed.

Originally posted by @silverwind in #23243 (comment)