Fixing typo that caused a shadow variable
NotifyUser and Space now use templates for emails

[#75149532]
Email templates can be overridden

- to override the space_body.text template, place space_body.text in the
  templates/overrides dir

[#75149532]
Simplifying Template loading

- EmailTemplatesManager handles loading templates and overrides
Pulled out service object for generating responses

- load uaa users before start sending emails
Adds specific test coverage to response task

[#75149532]
Removing nonsense test