fix: use secure: true instead of smtps:// in mailer

[spaenleh]

In this PR:

• fix Use smtp:// and set ‎secure: true for SSL/TLS #1921 Deprecation warning from NodeJs
  • add a MAILER_USE_SSL env var to control the use of SSL with the mailer. By default the value is to disable SSL in DEV and enable in PROD.
• update the compose file for self hosted services to disable SSL (most likely that we will run in PROD but we do not have support for SSL.
• add a helper function to convert an env var to a boolean value. it accepts true and 1 as truthy values any other value is considered false. We can provide a default value, when no default is provided, it is false.

[pyphilia]

If I understood correctly the docs, smtps in the connexion string was settings secure: true fine
https://github.com/nodemailer/nodemailer/blob/8033604aed6d107dd9d44f6ede4508de3393e504/test/shared/shared-test.js#L30 (also used in docs: https://nodemailer.com/smtp#creating-a-transport )

I've spent time to understand TLS, STARTTLS, etc... but it's a mess. I think the best article was this one https://mailtrap.io/blog/starttls-ssl-tls/#Which-ports-are-used-for-Implicit-and-Explicit-SSLTLS
And I think the key of all this was: TLS is better than SSL. SMTPS was refering to SMTP+SSL, but today it also means SMTP+TLS. I think as long as we use TLS we are fine. So secure: true with port 467.

In the end I think using smtps in the connexion string was okay (since it results in secure=true), anyway this string is there to be stripped. I'm curious what was your source for deprecation.

https://docker-mailserver.github.io/docker-mailserver/latest/config/security/understanding-the-ports/#overview-of-email-ports

[pyphilia]

LGTM! Thanks for this PR 🧶

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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