Add API endpoint to sync users for LDAP

Description

Some users are using the API to programmatically create groups and there isn't an option to sync automatically through the API. The only option is to hit the “sync now” button under the “manage access” tab for the group.

Proposal

Add API end point to sync users

Links / references

https://gitlab.zendesk.com/agent/tickets/75070

Makes perfect sense. Should this moved to the EE tracker?

@stanhu Thanks, Stan

This is something we should just do, and it should be an easy fix.

/cc: @mydigitalself

added user management label

changed milestone to %9.4

added Stretch label

Unfortunately, I've had to push this out a few releases as we've had too many requests on our plate to deal with.

changed milestone to %10.0

removed Stretch label

added Deliverable label

assigned to @mkozono

added In review label

mentioned in merge request !2785 (merged)

closed via merge request !2785 (merged)

mentioned in commit afa2cb2b