Add loading indicator in the Ban/Unban

[BlagovestGerov]

Add loading indicator while the request to Ban/Unban user is in process or/and add message notification (angular toaster notification). We have implemented such in other places in the admin app.

[evereq]

@AdemHodzic some more improvements to be done:
a) Make button Ban/Unban disabled, during the request process.
b) In the Toaster notification add the user name. For example “Annabel O’Keefe is banned!“.