ms3 1.1.0: Experimental MuseScore 4 support

This version does not throw errors when trying to parse files created by MuseScore 4. Parsing these files has not
sufficiently been tested but so far it was looking good. The fact that MuseScore 3 is able to read such files shows
that not much has changed in the file format itself.

The command ms3 convert has been updated to support MuseScore 4 executables. With the current MuseScore 4.0.0 this
is not quite straightforward because conversion to .mscz via the commandline isn't currently working and conversion
to .mscx, if it works at all, deletes the contents of the target directory
(issue #15367). The new function
utils.convert_to_ms4() offers a workaround that creates temporary directories to store the
"Uncompressed MuseScore folder" and then copies the .mscx file to the target directory (default) or zips the
temporary directory into an .mscz file (parameter --format mscz). For all other target formats, the output
will correspond to what the MuseScore 4 executable yields.