Enable canvas authentication on the UToronto staging hubs

[agoose77]

We will update the staging hub to use Canvas OAuth authentication. This work does not capture the need to provision credentials, which is an unquantifiable external blocker.

See the statement of work for more information.

Given that the storage is shared across all hubs, we won't migrate any data as part of this work. For utorid as the identifier, should mean that all users have fresh home directories, unless we expand the utorid to a full email.

Definition of done

• The staging hub is configured with GenericOAuthenticator using UToronto-provided canvas credentials.
• The r-staging hub is configured with GenericOAuthenticator using UToronto-provided canvas credentials.
• Access to these hubs from UToronto user accounts (via Canvas) is tested