clarify app and publisher information on Windows

[ronso0]

when installing and running Mixxx on Windows 10 I came across a few unclear infos and inconsistencies that may put off inexperienced users.

again, this was with an msi created by github actions. maybe those don't use the proper credentials but official release/beta installers do? (didn't test those because I avoid to stay in Win longer than necessary, always get a feeling of opression there, and ux drives my mad)

1) when installing a msi that is actually named mixxx-something-... there pops up a warning
  "Do you want to allow this app to make changes..?"
  bold name: 12cbb.msi
If I wouldn't have known it's Mixxx my alarm would have gone off for sure.
Here, the publisher is mentioned, but only a few may know Russel John Skerry-Ryan ;\

2) Later on, Windows Defender warns about Mixxx-HEAD-r.... but Publisher is unknown

[Be (be.ing)]

> Here, the publisher is mentioned, but only a few may know Russel John Skerry-Ryan ;\

IIRC it costs much more to buy an organizational certificate than a personal certificate for singing Windows binaries.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/10380