Simplify user permissions for the first user in Connected PMM

The problem: When the admin/admin user connects his PMM server  to Percona Portal he needs to do the next steps:

1. as an Admin (admin/admin default ) to go Settings and enter credentials for the Percona Account ([email protected] / password) and other details 
2. Connect PMM and Percona 
3. Login as  [email protected]  and see very little information, as he is Viewer by default 
4. Logout  as [email protected] 
5. Login as admin/admin 
6. Go to User management and make [email protected]  - Admin user so  he can continue using PMM
7. Logout as admin/admin
8. Login as [email protected]  and be an  Admin

This is a very complicated and hard process, we need to find a way to simplify it to this first user. 

Proposed UX:

When the user admin/admin enters Percona Account credentials ([email protected]) for Connect PMM and Portal  - also make this user   [email protected] an admin, so the moment user logged as [email protected]  he/she is an Admin in PMM and no need of additional actions. 

See also:

PMM-9318