HaikuDepot: Nickname Length

HDS has increased the length of the nickname to
32 characters on version 1.0.147 and this change
supports that change in the desktop client.

Resolves to #18343

Change-Id: Iae07acc165165e91b04cef7ebc1190d241d9a053
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6307
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: waddlesplash <waddlesplash@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>