Small refactoring of the Makefile

Some clean up, some reformatting for better readability and some additions like environment variables that are new considered:

• TANGO_HOST
• NETWORK_MODE
• MYSQL_HOST

docker-compose/Makefile

@@ -2,8 +2,9 @@
 MAKEPATH := $(abspath $(lastword $(MAKEFILE_LIST)))
 BASEDIR := $(notdir $(patsubst %/,%,$(dir $(MAKEPATH))))
 
+DOCKER_COMPOSE_ENV_FILE := $(abspath .env)
 COMPOSE_FILES := $(wildcard *.yml)
-COMPOSE_FILE_ARGS := $(foreach yml,$(COMPOSE_FILES),-f $(yml))
+COMPOSE_FILE_ARGS := --env-file $(DOCKER_COMPOSE_ENV_FILE) $(foreach yml,$(COMPOSE_FILES),-f $(yml))
 
 ATTACH_COMPOSE_FILE_ARGS := $(foreach yml,$(filter-out tango.yml,$(COMPOSE_FILES)),-f $(yml))