Login window for Allzpark

[jasperges]

In productions it can be helpful to have a user login to Allzpark. That way you can for example configure which projects are visible to the user, which software can be used etc.
Also when connecting Allzpark/Avalon to Kitsu, Shotgun or FTrack this can be helpfull.

How this login works in the background should be handled by some config or rez package. For us for example, the login mechanism would depend on the production tracking software being used (some projects use Kitsu, some use Shotgun). Other studios might have setup LDAP or whatever suits there needs. So I would suggest that you can configure if you want a login window and if so provide a function that accepts a username and password. Then the environment would be set up for that user (if the login is correct of course) and Allzpark is launched in that environment.

To have all information in one place, I'm also pasting @mottosso initial idea for an approach:

1. A mockup, to get on the same page and iterate on usecase/usability
2. A workaround, by throwing together a separate app based on QLineEdit, that launches Allzpark with some env variable set, e.g. ALLZPARK_USERNAME
3. An implementation, with optional login, configured via allzparkconfig.py