Allow user invite to include memberships

[BGWoodward]

Currently users can be given an invite link when inviting to an organization. Once created, a secondary step of creating memberships for that user must be taken, which can result in a lag of a user making an account and seeing any projects when they login. Often this results in confusion, and emails are received along the lines of "I made an account, but I don't see anything...". This is a friction point, and what happens is that to avoid that friction some default back to making manual accounts with default logins, which we want to get away from.

The request is to be able to select projects and membership levels to be part of an invitation to create a Tator account.