Remove hardcoded paths

Use the preflight settings passed in by the notification
manager.  This allows this preparation to be reused.
Consolidate project reply notifications

There was no need for the same code to be implemented almost
exactly the same in both prepareProjectCommentReplyOwnerEmail
and prepareProjectCommentReplyParentEmail.  Combined those
into a single preparation file and updated the settings to
use this strategy.

Update the HTML/Text templates for project comment replies
to match the content that we want.  Update the subject lines
to be underscore templates in the config.