Add User Account Page

[volkflo]

Currently you do not see the logged in user.

What should be done:

Show user avatar next to logout button when you are logged in.
By clicking the avatar the user-account page should be opened (that of course must be updated / fix styling)
username
email address
keycloak role (e.g. apiuser => Access to API Management UI)
membership for organization member (only shown when you are apiuser, not a developer user)

Future improvements:

Change locale (via keycloak account page)
Change password (via keycloak account page)