Improve docs on choosing a mailing provider
Created by: seancolsen
Awesome content here comparing various mailing service providers:
https://civicrm.org/blog/andrewhunt/alternatives-to-mandrill
This would be great to include here:
https://docs.civicrm.org/sysadmin/en/latest/setup/civimail/
Note: as described in #19 (closed) that Sysadmin Guide content currently needs quite a bit of clean up.