Add a way to Remove User from a Role

[elaurentin]

Is your feature request related to a problem? Please describe.

To supplement existing workflow AssignUserToRole, add the following Activities:
RemoveUserRole: Remove a User from a role. This is very similar to AssignUserToRole but the ExecuteAsync to remove the user from a role instead

SelectUsersInRole: This activity to output users list (or email) as property to create a mailing list to send email or notifications.

This is to supplement:
User Workflow: User created event and assign user to role #3489

Describe the solution you'd like

RemoveUserRole: has same properties as AssignUserToRole but implementation calls
await _userManager.RemoveFromRoleAsync(user, roleName)
in the ExecuteAsync handler

SelectUsersInRole: this activity has 2 properties and will create a workflow output variable:
PropertyName: the workflow property output name to create, which can then be reused through expression
RoleName: the User Role to get all users name or email

Describe alternatives you've considered

The activities AssignUserToRole and RemoveUserRole can be combined as UpdateUserRole but this would break the interface.
SelectUsersInRole, may need to readjust the activity name for OC. Also, may need a different parameter to select the field for "UserName" or "Email".

[MikeAlhayek]

@elaurentin can you submit a PR for Remove User Role Task? the implementation should be very simple here and should be almost clone of AssignUserRoleTask.

Maybe you can enhance the Display Driver UI but letting the user select (using a checkbox list) which roles to update instead of a text box.

[elaurentin]

I just realized that putting a listbox (dropdown) may actually break existing code if a Liquid expression was used. I will submit my PR soon. Thanks!