Easily invite multiple users to one or more projects

[allanlasser]

Some additional feedback from a user who makes heavy use of projects in their organization.

• If they could invite multiple users at once to a project, that'd be good.
• If they could invite multiple users to multiple projects at once, that'd be even better.
• If they could share a project with their organization and skip inviting altogether, that'd be the best.

[eyeseast]

This is a backend issue, but it would be nice to be able to invite people using any email address they have registered in Squarelet. I always have to check which email people use.

[eyeseast]

Another nice-to-have: Can I invite a collaborator in my org without typing their email?