HaikuDepot: Languages List

Abstacts the list of supported languages into
the LanguageModel class preventing use of
List. Also; fix a few cases where newer
logging techniques may have caused incorrect
logic flow.

Relates To #15534

Change-Id: I144fe4788abdaf0d93e53eeabc97b3f7aa2ec710
Reviewed-on: https://review.haiku-os.org/c/haiku/+/3085
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>

HaikuDepot: Refactor of Login

These changes cover a rework of the login and
account creation logic before making additional
changes related to the user usage conditions.

Relates to #15209

Change-Id: I90b7dbcee5b0285476938c6ced0afc89483d6227
Reviewed-on: https://review.haiku-os.org/c/haiku/+/2023
Reviewed-by: Stephan Aßmus <superstippi@gmx.de>
Reviewed-by: Adrien Destugues <pulkomandy@gmail.com>