New team member onboarding process

We're missing clear process of adding new people on project i.e. "I want to join team" and "Team member wants to add new person".

"I want to join team" process should notify (via email) founder/maintainer/owner of project. 

When "team member adds new user to the team" Laddr should send email notification to user "You've been added to the %project_name%".
