All keymaps should specify what the Mac keys do

[rq]

While performing a little test for #6488, I just noticed that of all the keymaps that Haiku ships, only three ('Check (Mac)', 'French (Mac)' and 'German (Mac)') specify what the "=" key, which is present in numeric keypad area on Macs, enters. While this key is probably specific to keyboards designed for Apple, it doesn't make any sense to keep that button without an assigned function in all the other keymaps. I think it's quite obvious that that button should enter the Equals character by default, so I suggest to just add this key to all keymaps which don't have it specified.

Additionally, when I choose the Apple Aluminium Extended International keyboard, I can see seven unspecified keys at the end of the top row. I think it makes all possible sense to assigned them some functions as well.