This patch configures postfix to reject incoming email from its own
domains this is an effort to fight phishing of emails from my own domain
claiming to be from postmaster or alike.

References:
https://superuser.com/questions/964958/make-postfix-reject-incoming-email-spoofed-as-from-my-own-domain

This patch removes elasticsearch from the mastodon container image, as
it's not used in production anyway. Therefore the removal will simplify
the upgrade process finally allowing an idempotent upgrade to 4.2.1.