Make sass-watch script work with webpack

Works in the same fashion as it did with setuptools. To be improved/replaced with webpack's plugins and features

tools/docker/sass-watch.sh

@@ -4,5 +4,5 @@
 cd /source
 while inotifywait -e modify -e move -e create -e delete -r --exclude \# /source/python/nav/web/sass
 do
-  python3 setup.py build_sass
+  (cd python/nav/web/static/js && npm run build:sass:prod)
 done

tools/docker/supervisord.conf

@@ -13,9 +13,9 @@ command = /source/tools/docker/nav-start.sh
 autorestart = false
 startsecs = 0
 
-; [program:sass-watcher]
-; user = nav
-; command = /source/tools/docker/sass-watch.sh
-; stdout_logfile = /var/log/supervisor/%(program_name)s.log
-; redirect_stderr=true
-; autorestart = true
+[program:sass-watcher]
+user = nav
+command = /source/tools/docker/sass-watch.sh
+stdout_logfile = /var/log/supervisor/%(program_name)s.log
+redirect_stderr=true
+autorestart = true