Fix adminarea and emails for new membership logic

app/controllers/profiles/notifications_controller.rb

app/mailers/emails/groups.rb

app/mailers/emails/projects.rb

app/models/user.rb

app/services/notification_service.rb

app/views/admin/groups/show.html.haml

app/views/admin/projects/show.html.haml

app/views/notify/project_access_granted_email.html.haml

app/views/notify/project_access_granted_email.text.erb

app/views/profiles/notifications/show.html.haml

app/views/projects/team_members/_group_members.html.haml

spec/factories.rb

spec/factories/users_groups.rb

spec/mailers/notify_spec.rb

spec/requests/api/branches_spec.rb

spec/requests/api/commits_spec.rb

spec/requests/api/project_members_spec.rb

spec/requests/api/projects_spec.rb

spec/requests/api/repositories_spec.rb

spec/services/system_hooks_service_spec.rb