Add support for Google Authentication

[rowleya]

Allow Google authentication here, which can then be used by our local Jupyter server. This may need a bit more thought since there are certain things in the OpenID login that rely on EBRAINS things, like Collabs and Quota.

[Christian-B]

can google users not use private clooabs as setup in #1296

[Christian-B]

The whole Collabs and Quota stuff has been a lot less useful than planned so this may even be the motivation for stripping that completely out.

[rowleya]

We do use the quota and collabs, but only from EBRAINS. A Google user would probably have no specific quota; this would be left to EBRAINS for now.