setting `LIVERELOAD_HOST` in container/VM/similar

[elmcrest]

Hey, just wanted to report this: If you set the LIVERELOAD_HOST in settings.py this host is also used in the javascript to conntect to the livereload backend, this breaks functionality in case of (dev-)container/VMs/similar setups because the backend needs to f.e. start with 0.0.0.0 but the script still needs a specific host like f.e. 127.0.0.1 in case of docker containers. this might be not needed on a "real" docker environment like a Linux OS as the base - but there are still use cases left (besides Windows and macOS).

So, solution would be "just" to have two settings I guess ... something like LIVERELOAD_HOST and maybe LIVERELOAD_BACKENDHOST or _TARGET_HOST or something else :) - naming is a bitch :)

cheers