Display additional user information about oauth accounts

[tcompa]

Starting from fractal-server 2.5.0a1 (upcoming), user-related endpoints will also returns some information about their associated OAuth accounts (if any). This includes a new property oauth_accounts, where each element includes properties: id, account_email and oauth_name (e.g. github or whatever we used in the fractal-server OAuth configuration).
If there is no oauth account linked to a given user, then oauth_accounts=[].

We should include this information in the user profile and in the user information in the admin-area page.

[tcompa]

2.5.0a1 now released

[zonia3000]