Add 4 lute fingering symbols to mscore font / Remove Thumb from Fingerings palette

This is in preparation of a more complete support for historic tablature to be added later.

The 4 symbols are added to the mscore font in the SMuFL code points. Currently, they are not correctly positioned, much like the other symbol-based fingering, i.e. the cello thumb position.

These glyphs are not added to any palette yet, as they require a proper positioning. For the same reason the cello `Thumb position` is removed from the fingering palette. The latter is anyway included also in the Articulations and Ornaments palette where it is dealt with more properly.