Filter admin endpoint to list users with locked status

[hanadi92]

Description:

As the current behavior of the list users admin endpoint /_synapse/admin/v2/users?query_param=value allows the requester to filter the returned users list with some user properties like ?deactivated=boolean to indicate whether to include deactivated users or not. It would be great to include the newly introduced user property locked as a filter to the list with ?locked=boolean.

Expected behavior: when locked=true include locked users to the returned list, and vice versa.