Revert "Handle HYDRA_EMAIL_TEMPLATES that are paths"

This doesn't work as planned, will re-work.

This reverts commit d2ce7747a0a44c1278361d69af1d53d193fdc6c8.
Revert "Emable overriding the email template."

This doesn't work as planned, will re-work.

This reverts commit 304f8a5714371ede4438d07c04b22ba0e734c817.