The friend right-click menu only opens for online players, so notes
could not be edited on offline friends. The full menu is useless
offline anyway (Whisper/Invite/Target need an online player), so open
a menu of our own with just the note editor for offline friends.
Squashed from the classicapi-next branch:
- Read spell fields through ClassicAPI instead of nampower (libdebuff, swingtimer)
- Read friend and who-list class tokens from C_FriendList (socialmod, libunitscan)
- Count online friends with C_FriendList.GetNumOnlineFriends
- Add a friend notes module (modules/friendnotes.lua)
- Bump ClassicAPI minimum version to 10906