Allow access request to be enabled/disabled for groups/projects via API

Zendesk issue: https://gitlab.zendesk.com/agent/tickets/33423

It's not currently possible to toggle the 'request access' feature for groups and projects when creating/updating via the API. Some customers solely created groups and projects via the API so this ability is critical.

This should be pretty easy - expose the attribute in each endpoint. @JobV Please schedule.