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.
This PR aims to close#14253
We keep the default behavior using the Coder logo if there's no logo
set.
Otherwise we want to use the logo based on the URL set in appearance.
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Co-authored-by: defelmnq <yvincent@coder.com>
