improved docker / container support

[jusito]

Issue #705

• allow to disable auto update -> added update_rs(..., $mode = 'default') possible to set from environment variable for none/major/minor/patch, if variable isn't set same behavior as before
  • fix explicit version checks
• create dbconfig if not exists in php
  • add migration from old other/dbconfig.php -> config/db.php
• worker.php status checks for
  • process running
  • ts3 connection successful
  • last update successful
• all changes tested

1. Iam not experienced in PHP so a review before removing WIP is mandatory in my opinion.
2. Is there an prefered testing method?
3. Do you prefer a two step pr? E.g. first for changes needed in preparation but without Dockerfile?