18.03 on debian stretch - slim

[mwlczk]

• Upgrade to Debian 9.4 (I've been running on Debian stretch 9 for 3 months now).

• rearranged the requieredPackages and buildDep-Packages aswell as as lowered the amount of layers a bit.

• Upgrade ejabberd to 18.03

  • certfiles specific changes
  • rename dh.pem to dh.dhpem so it does not give errors while being parsed (*.pem) as a certificate-file

• changed some ejabberd.yml settings to avoid deprecated modules (bosh instead of http_bind; mod_stream_mgmt).

• changed some ejabberd.yml to be more compliant with conversations ComplianceTester.

[mwlczk]

Hi, I am happy this got merged. Keep in mind the dh.pem is being regenerated as dh.dhpem again and thus might take long on the first start! You should remove the old dh.pem to avoid error messages in the log. Alternatively this could be handled in the run-script, but I won't be able to provide a PR this weekend.

[rroemhild]

God point. I'll look into this. Thank you for your contribution!