Review the `remote` package structs and trim them to contain only the fields that are being used

The structs in the remote package are generally derived from the msgraph data model. The conversion of remote package structs to provide google calendar structs are generally incomplete, as we only translate the fields that are necessary for use.

The task here is remove fields that are not used, for each struct exported by the remote package. This way, there is no chance that the gcal → remote conversions are missing a necessary field. We also need to verify that the conversions handle all of the fields being used.

Acceptance criteria

• Remove fields that are not used, for each struct exported by the remote package.
• Ensure that both providers are using all the fields.
• Ensure that no removed field is being used by a provider.