Ability to disable SMTP TLS verification

Created by: slimsag

With two customers we have seen them only have SMTP servers with TLS verification disabled, meaning sending mail is not possible due to an error like:

internal API response error code 500: x509: certificate signed by unknown authority\n (http://127.0.0.1:3090/.internal/send-email)"

Currently, the only way to workaround this issue is by acquiring the CA certificate for the SMTP server (the customer has to know where to get this, usually from the team that manages the SMTP server) and then appending that to the existing /etc/ssl/certs/ca-certificates.crt in the frontend containers (docker-compose: just frontend-internal container, single-container: just the single server container).

You can extract the CA certificates file from the running container like so:

docker exec -it $CONTAINER cat /etc/ssl/certs/ca-certificates.crt > ca-certificates.crt

Then, append your SMTP server's CA certificate to the ca-certificates.crt file it produces and then mount that into the container by altering the docker run command to add:

-v myconfig/ca-certificates.crt:/etc/ssl/certs/ca-certificates.crt