FID as main identifier, not nickname

Because user can don't have a game so no nickname, but his
FDEV tokens still suits for not CAPI requests (i.e. squadrons api)

capi/exceptions.py

@@ -1,6 +1,14 @@
-class RefreshFail(Exception):
+class CAPIException(Exception):
+    pass
+
+
+class RefreshFail(CAPIException):
     def __init__(self, message: str, status: str, state: str):
         self.message = message
         self.status = status
         self.state = state
         super().__init__(str(self.message) + ' for ' + str(self.state))
+
+
+class NoFID(Exception):
+    pass