Related to #17082
Some notifications ( workspace created and workspace manually updated )
are using wrong variables to build the Action URL. Fixing it.
This PR aimes to [fix this
issue](https://github.com/coder/internal/issues/448) -
The main idea is to remove greetings from templates stored in the DB -
and instead push it into the template for require methods - for now
SMTP.
Relates to https://github.com/coder/coder/issues/15845
When the `/workspace/<name>/builds` endpoint is hit, we check if the
requested template version is different to the previously used template
version. If these values differ, we can assume that the workspace has
been manually updated and send the appropriate notification. Automatic
updates happen in the lifecycle executor and bypasses this endpoint
entirely.