Docker simplifications and improvements

[timar]

• Target version: 23.05.5

Summary

Simplifications and improvements after @Minion3665's work.

Details

• with PR Add cli option to use settings from env variables #7160 we could get rid of docker/from-packages/scripts/start-collabora-online.pl and chunks of docker/from-packages/scripts/start-collabora-online.sh
• with PR Stop coolwsd when /etc/coolwsd/coolwsd.xml changes #7145 we could get rid of the inotify-tools dependency
• SAL_LOG setting was unnecessarily duplicated here, by default core logging is disabled in coolwsd.xml
• Generation of WOPI Proof Key is not necessarry here, as it is better to generate and maintain it outside of the container, and mount it, if needed.

TODO

• get rid of docker/from-packages/scripts/start-collabora-online.sh. The last bit there is automatic SSL cert generation.
• update docs, if someone does not want automatic restart after config file change, then --o:stop_on_config_change=false should be passed in extra_params, but I don't think it's a common use case, when config files change in the container which should be immutable ans stateless anyway.