MVC API endpoint to allow admin to disable invite by email through the API
Overview
Add an MVC backend only API to allow administrators to disable a particular API endpoint, invite by email through API. See #324718 (comment 546460848)
* [ ] Add an instance admin setting to disable invite by email through the invitations API
* [ ] May need follow up issue(s) to handle this change gracefully and with appropriate messaging in UI elements that use this API.
Edited by Phil Calder