Rework postfixes conf

[lpoujade]

main changes:

• remove relay container
• app now connects only to outsmtp to send mail (validation, report and alerts)
• outsmtp allows relaying from
  • authorized servers (manually added in domain configuration) for known users
  • docker network on port 10025 (already the case for outamavis, now also used by app)
  • $SMTP_TRUSTED_PROXIES if set
• smtp (for incoming mail) no longer check spf (done by amavis)
• use postfix MAIL_CONFIG to specify which conf folder to use
• simplify/update postfixes conf
• policyd-rate-limit: no hardcoded limit + no logs
• tests:
  • add test for report mail
  • be more precise when searching mail via mailpit api
  • fix a "bug" hiding problems when some vars were not set

~~break tests because of outsmtp which now accepts mails from others containers, so not blocking badrelay~~ fixed

Related issue(s)

close #110
#175

How to test manually

Reviewer checklist

• [ ] Code is manually tested
• [ ] Interface works on both mobiles and big screens
• [ ] Interface works on both Firefox and Chrome
• [ ] Tests are up to date
• [ ] Documentation is up to date
• [ ] Pull request has been reviewed and approved

[lpoujade]

@marien-probesys @ctresvaux j'ai plus ou moins intégré les récents changements lié à l'envoi du mail de verif mais je veux bien un coup d'œil de votre part !

[marien-probesys]

Je pourrai regarder pour corriger les problèmes PHPStan, je te laisse regarder mes remarques avant.

[lpoujade]

Je pourrai regarder pour corriger les problèmes PHPStan, je te laisse regarder mes remarques avant.

Est ce que tu pourrais commit aussi tes remarques sur le php en même temps ?

[marien-probesys]

@sparunakian je peux te laisser revoir les dernières modifs de Loïs concernant la partie smtp ? Ça dépasse mon champ de compétence ici. Je me chargerai ensuite de merger la PR proprement.