accounts: show table row when clicking into details, more usage of

RadioBasedTabs

when clicking a username in the accounts tab, the details comes up with
a copy of the row you clicked, so you can view logs and edit the user.
Also decided not to use a RadioBasedTab here, instead providing a link
to the activity tab with a search for the user (added the ability to do
that, ?user=username). FIXME: handle deleting the user or just generally
editing them.

lang/admin/en-us.json

@@ -7,6 +7,8 @@
         "invite": "Invite",
         "accounts": "Accounts",
         "activity": "Activity",
+        "activityFromJF": "Activity (from Jellyfin)",
+        "activityFromJfa": "Activity (from jfa-go)",
         "settings": "Settings",
         "inviteMonths": "Months",
         "inviteDays": "Days",