Add a new capability "USERREGISTRATION"

[simpleidserver]

• In the authentication methods, display the "USERREGISTRATION" tag.
• Add an element to filter on the tags.
• In the ACR view, display the authentication methods with the flag "USERAUTHENTICATION".
• In the authentication methods window, explain the different tags : User Authentication : authenticate the user. User Registration : support credential enrollment. ** Push notification : capable of receiving notifications from the identity server.