Dropped stored role name/description and other superflous fields

For name and description, we'll derive these from the role_field and
content type, which is much better for lots of reasons (eg changing text
the future). Also ditched the rest of the fields comming from the
standard common base model, we didn't use them and they cost several
indexes on the table.

awx/main/fields.py

@@ -92,9 +92,7 @@ class ImplicitRoleDescriptor(ReverseSingleRelatedObjectDescriptor):
 class ImplicitRoleField(models.ForeignKey):
     """Implicitly creates a role entry for a resource"""
 
-    def __init__(self, role_name=None, role_description=None, parent_role=None, *args, **kwargs):
-        self.role_name = role_name
-        self.role_description = role_description if role_description else ""
+    def __init__(self, parent_role=None, *args, **kwargs):
         self.parent_role = parent_role
 
         kwargs.setdefault('to', 'Role')
@@ -104,8 +102,6 @@ class ImplicitRoleField(models.ForeignKey):
 
     def deconstruct(self):
         name, path, args, kwargs = super(ImplicitRoleField, self).deconstruct()
-        kwargs['role_name'] = self.role_name
-        kwargs['role_description'] = self.role_description
         kwargs['parent_role'] = self.parent_role
         return name, path, args, kwargs
 
@@ -190,11 +186,7 @@ class ImplicitRoleField(models.ForeignKey):
                 if cur_role is None:
                     missing_roles.append(
                         Role_(
-                            created=now(),
-                            modified=now(),
                             role_field=implicit_role_field.name,
-                            name=implicit_role_field.role_name,
-                            description=implicit_role_field.role_description,
                             content_type_id=ct_id,
                             object_id=instance.id
                         )
@@ -247,12 +239,7 @@ class ImplicitRoleField(models.ForeignKey):
                 if qs.count() >= 1:
                     role = qs[0]
                 else:
-                    role = Role_.objects.create(created=now(),
-                                                modified=now(),
-                                                role_field=path,
-                                                singleton_name=singleton_name,
-                                                name=singleton_name,
-                                                description=singleton_name)
+                    role = Role_.objects.create(singleton_name=singleton_name, role_field=singleton_name)
                 parents = [role.id]
             else:
                 parents = resolve_role_field(instance, path)