classes-global/license: Move functions to library code

classes-global/license: Move functions to library code

Moves several of the functions in license.bbclass to be library code

New function dependencies were manually verified using bitbake-dumpsigs
to ensure that bitbake identified the same dependencies even though they
are now in library code (although the new function names mean that the
task hashes still change)

Signed-off-by: Joshua Watt <JPEWhacker@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 0333e04e353991260c5f67a72f80f3ab9dcf526a)