I envision the StylesController as the source of information about
styles settings in both the editor and renderer.
We will add email styles settings and these will be accessed in PHP via this service.
[MAILPOET-5540]
In this commit, I copied the code for processing the rendering of emails
from the current renderer.
This will allow us to use different base templates and styles.
Ideally, we should be able to add hooks and reuse the renderer from the engine namespace in
the current renderer.
[MAILPOET-5540]
