Check or add some info about the `DEV` environment variable

As per v3.4, this is what is currently reported in the /scripts/docker-entrypoint.sh file:

g3w-suite-docker/scripts/docker-entrypoint.sh

Lines 15 to 18 in e435dcc

    
           # When building in dev env you might want a clean build each time. 
        
           if [[ -z "${DEV}" ]]; then 
        
             rm -rf /shared-volume/build_done 
        
           fi

Check if the variable is still in use or else give us some information on where it is actually set.

NB the following published compose files do not list any DEV variables:

	# When building in dev env you might want a clean build each time.
	if [[ -z "${DEV}" ]]; then
	rm -rf /shared-volume/build_done
	fi