Adding a "Dancer" like fruity Dance from FL Studio

Nobody has claimed this yet.

I made a functionality very similar to the chibi chick from FL Studio that dances to your main Song when its playing. Started as a joke but already works. It uses a Subwindow but frameless and transparent. I avoided messing with the base code the best I could so its integration could be easier. It uses the same sprite-sheet dimensions as the original Fruity dance so it should be themed as well (We can't use the same design I suppose). I tried it to make it a plugin but there was too much abstraction so I just made it as a regular window.
This is the test
[output.webm](https://user-images.githubusercontent.com/55648441/224191389-bc82c12c-b3a4-4f14-a678-decd4b04c74e.webm)
I have to do quite the refactor and documentation first but if someone is already working on something like this I could help. Appreciate recommendations or as well.
Forgot, if someone could please assign this to me as an enhancement.

Start by reviewing the existing Subwindow approach and the plugin abstraction discussed in the issue, then compare them with the working prototype. Clarify the refactor, theming, and documentation needed for a frameless transparent dancer that follows the main song. Done means the feature is integrated as a maintainable regular window and its sprite-sheet behavior is documented.

Written by the indexing model from the issue text.