Do we want broader instrument types/categories on UMIL?

This is related to https://github.com/DDMAL/UMIL/issues/336, where we discuss what is a new instrument versus an instrument label, but it specifically has to do with instrument categories. Take these three UMIL entries:

- [Lamellophone](https://umil.linkedmusic.ca/instrument/3648/) - the lamellophone is a sub-category of idiophone that comprises dozens and dozens of different instruments that all have a specific name. It's sort of like calling a guitar a string instrument and leaving it at that.
- [Church drums](https://umil.linkedmusic.ca/instrument/3356/) - what does this mean? Is any drum you put in a church a church drum? Or is this a general/antiquated term for a drum that has an actual name?
- [African slit drum](https://umil.linkedmusic.ca/instrument/3343/) - there are SO MANY African slit drums. This one irks me.
- [Transposing instrument](https://umil.linkedmusic.ca/instrument/3208/) - I mean...

@kyrieb-ekat, @annamorphism, @cguo88, do you have thoughts on this?

Start by reading linked issue #336 and reviewing the four referenced UMIL instrument entries. The issue identifies no file, test, or implementation entry point; completion would require an agreed policy for instrument categories and labels before any code or data changes can be scoped.

Written by the indexing model from the issue text.