Support the Google Picker for importing Google Drive data through file source templates

[natefoo]

The Google Drive file source template uses the drive.file permission which means that Galaxy can only access Drive contents that the user has created with Galaxy (and specifically, that Galaxy instance's (oauth2) application). This makes its usefulness pretty limited since you can't use Google Drive for importing arbitrary data.

Getting full access to Drive requires a verification process that we probably don't want to do, but there's an alternative: if we integrate the Google Drive Picker then files can be shared with the app at selection time. Annoyingly this sharing cannot be done through the standard Google Drive UI, as far as I can tell the Picker is the only option for it.

Maybe this is a bad idea, so please feel free to tell me so if it is.

xref: https://github.com/galaxyproject/galaxy/issues/19915 https://github.com/usegalaxy-eu/infrastructure-playbook/pull/1460