Feature/users invites

[kaareal]

This removes invites ... merge them into users.

• this makes it easier to manage ... not having to deal with multiple endpoints and ui
• this makes it easier to for assigning roles to users in without having to think of invites firsts, specially use for multiple org setup
• this makes it easier to have multiple orgs, as you don't have to add any scoping logic to invites, the user object already have that logic.

[kaareal]

@dominiek you should check this one out i think