Add more online metadata controls

[Hiviexd]

We currently have the ability to edit tags online, which has come very handy when fixing things in uneditable maps when needed, specifically for Ranked, or soon-to-be-Loved maps with an unavailable mapper, with the latter happening on a monthly basis.

While fixing tags is possible for us, we usually encounter maps that need fixes in other fields (artist/title/source), and for those we have to request peppy for an online fix. I was wondering if it'd be easier for everyone to instead have web capabilities for this, given we already have online tags, and especially with "hax-submits" being out of the picture for good reason.

Needed fields would be:

• Artist
• Artist (unicode)
• Title
• Title (unicode)
• Source

Permissions should be identical to the online tags editor.

[Joehuu]

Similar to #10108