Use AuthAlligator client to obtain access token

[thomasst]

• Support to add/update AuthAlligator accounts via API.
• Added back some Gmail auth code that we previously removed (we currently have a few accounts where auth fails retry forever), and also made it work for Microsoft accounts.
• Propagate the token manager's force_refresh parameter to AuthAlligator's verify method.

Example for adding an account:

curl -XPOST localhost:5555/accounts/ -d '{"type": "microsoft", "email_address":"[email protected]", "scopes": "the scopes", "authalligator": "{\"provider\": \"MICROSOFT\", \"accountKey\": \"abc123\", \"username\": \"00000000-0000-0000-xxxx-xxxxxxxxxxxx\"}", "client_id": "hello"}'