[SDESK-7464] - Create new async Users Resource and Service

[BrianMwangi21]

Purpose

This PR creates new async users resource and service:

• Implementing a new resource model for users
• Implementing new async resource service for users
• Implementing resource config for users and register it in users module

Solves: SDESK-7464

[BrianMwangi21]

@MarkLark86 a few questions :

1. For areas with self.datasourse in the previous service, do we have a similar attribute for new async resources/models ?
2. For the get function in the new users async service, should it be a custom one or should it override the find or search in the AsyncResourceService ?
3. Is there a current equivalent to self._validator() in the new AsyncResourceService ? Or is it to be accessed by a resource model like. It's used in the DBUsersService on line 603 :

        validator = self._validator()  # TODO-ASYNC: Confirm on usage of validator

[MarkLark86]

@MarkLark86 a few questions :

1. For areas with self.datasourse in the previous service, do we have a similar attribute for new async resources/models ?
2. For the get function in the new users async service, should it be a custom one or should it override the find or search in the AsyncResourceService ?
3. Is there a current equivalent to self._validator() in the new AsyncResourceService ? Or is it to be accessed by a resource model like. It's used in the DBUsersService on line 603 :

        validator = self._validator()  # TODO-ASYNC: Confirm on usage of validator

1. self.datasource is the same as self.resource_name in the new async services
2. Don't worry about the get function, this will be done on the REST API later
3. Also don't worry about validator, as it's used by functions not required by this PR

[MarkLark86]

Looks good, just a couple small things then this one should be good to go

[MarkLark86]

There is also a superdesk.tests file, which this module overrides causing an exception to be raised when running the app.

Could you move the content of that original file to this one, and delete the old one as well please

[MarkLark86]

After further inspection, looks like this one is not needed here either, as it is in the context of an API request.

It's functions like these should not go into these new async resource services, but instead the REST API (when we implement the User one).

We want to keep the separation of concerns with the new code, by separating out the data and request layers specifically. This should help keep these two concerns smaller, easier to read etc

[MarkLark86]

id shadows the built-in function with the same name. It would be good not to use names that are built into the python language