Add footnote capability

Footnotes are not footers. They attach to a note or an element and are displayed above the footer of the page (alternatively at the end of the score). If the layout changes and the anchor element is flipped on another page, the footnote changes page accordingly. But if the note simply changes position within the page, the footnote doesn't change in any way.
Also, one handy feature of footnotes is when they can be auto-numbered (Arabic numbers, letter, *, ...)
Text frames are a heavy workaround but really not ideal.

Footnotes are very important in critical editions, where you need to annotate the score about style, technique, errors in the source. And such editions get more and more demanded.

I'm filing it in accordance with the request done in the forum here