chore(core): remove QIT_VKEYDOWN, QIT_VKEYUP, QIT_VSHIFTDOWN, QIT_VSHIFTUP

[mcdurdin]

These four actions have never been officially supported, have only ever sorta worked on Windows (race conditions galore), and only one keyboard in the keyboard catalogue attempts to use them (gandhari, emitting () and then K_LEFT); bu_phonetic has some strange no-op kinda rules with them which would need correcting.

So:

1. Remove them (and fixup subsequent compile errors in keyboards repo)
2. Update compiler to error on VKEY out in all cases (see chore(developer): add warning or error if virtual key used in output of rule #10059)
3. Update documentation which hints at support on Windows.

This simplifies the #9999 action queue <--> struct work.

Identified while preparing for #10052.

Note that Windows continues to use these identifiers internally in keyman32, and has its own separate header file declaring them. Don't change this at this time.