HaikuDepot: Token Based Authentication

This switches the application over from using basic
authentication to using token-based authentication in
preparation for later using Open-ID based
authentication flows. The application version is also
bumped in order that the server can detect this version
at some later date in the future when it no longer
supports basic authentication itself.

Change-Id: I7addde1d57503c58d6bcd54908f22f66830c0c59
Reviewed-on: https://review.haiku-os.org/c/haiku/+/6944
Tested-by: Commit checker robot <no-reply+buildbot@haiku-os.org>
Reviewed-by: Jérôme Duval <jerome.duval@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>

HaikuDepot: Display User's Usage Conditions

A HaikuDepotServer may have previously agreed to
user usage conditions. If this is the case then
they are now able to view those conditions. There
were some problems with date formatting in this
change and so the date formatting logic has moved
into the HaikuDepot source code temporarily until
issues with the BDateTime class can be resolved;
most likely as a separate piece of work.

Relates to 15209

Change-Id: Ic3e5413d9139f410d7f7e8b566d4c56352dd2778
Reviewed-on: https://review.haiku-os.org/c/haiku/+/1870
Reviewed-by: Stephan Aßmus <superstippi@gmx.de>