Add files for custom lines Postfix & Dovecot
After updating to 3.2.2, I saw my whole Dovecot config was overwritten. Luckily I keep versioned backups so my dsync setup and stuff like that wasn't lost. But to make upgrading more easy, I think it would be a good idea to let the installer use 2 files from conf-custom (if they exist) that take precedence with the lines set it in, like we already do for configuration that's postfix version dependent.
So we could have a
custom_dovecot.conf in the conf-custom folder with only our own custom lines.
e.g. for postfix:
message_size_limit = 31457280
smtpd_tls_mandatory_ciphers = high
which will overrule the parameters we set in our templates.
for dovecot, we could let it overrule and if the line doesn't exist, add it.
Not sure how difficult this would be to implement in the installer. I'm curious what others think about this.
I think this would make upgrading for our users a more fluent task so they do it without hestitating in the future.