Create an API endpoint for inserting a new role

[jaytula]

This issue requires #184 to be resolved before it can be done.

We need an endpoint added in Next for inserting a new role to the roles table. It would be with the apis in the admin/roles folder and create.ts file.
That structure will give us the desired endpoint /api/admin/roles/create.

It should accept a POST request with a JSON body like:

{
  "name": "admin"
}

Note that this endpoint's access has to be restricted by either permissions or roles at some point.

As there isn't a UI at the moment, test that the endpoint is working with Postman or curl