Provide email.rb an option for Log Message to go before Changed Paths.

This is not complete, but I wanted to show my intent and open a dialog on requirements to get this integrated.  

This is for the Email service to be able to place the 'Log message' above 'Changed paths'.  The aim is to add a new option 'Log message first' on the page Settings > Webhooks & Services > Services > Email.

One query - I am not sure what a new boolean option will return for existing users  of the Email service.  In naming the variable 'log_message_first' I have assumed this will be 'false' by default for existing users of Email who have not configured it.   Could someone confirm that?

cheers -Ben