Remove much of the old legacy pose library:
- Remove from the Pose & Armature menus.
- Remove from the default keymap.
- Pose Library panel in Armature properties: Add "(legacy)" to title.
- Add note that the functionality of that panel is obsolete, with a
button that opens the manual on the chapter of the new pose library.
- Add button to convert the selected legacy pose library to pose assets.
- The rest of the functionality is greyed out to further communicate
it's been deprecated. It's still functional, though.
Ref: T93405