Improve development workflow in docker (#5079)

* Allow bower install of frontend components as root. Needed for frontend development in docker since everything runs as root in the docker image.

* Improve development workflow in docker

* Use LANG=C.UTF-8 in tox. Fixes installation of libraries with UTF-8 in it's readme.

* Install mysqlclient psycopg2 uvloop after requirements_all.txt again, but with a --no-cache-dir this time. Allows bootstrap_frontend to be executed in a different path like the other scripts.

script/build_frontend

@@ -1,22 +1,30 @@
+#!/bin/sh
 # Builds the frontend for production
 
+# Stop on errors
+set -e
+
 cd "$(dirname "$0")/.."
 
-cd homeassistant/components/frontend/www_static
-rm -rf core.js* frontend.html* webcomponents-lite.min.js* panels
-cd home-assistant-polymer
+# Clean up
+rm -rf homeassistant/components/frontend/www_static/core.js* \
+       homeassistant/components/frontend/www_static/frontend.html* \
+       homeassistant/components/frontend/www_static/webcomponents-lite.min.js* \
+       homeassistant/components/frontend/www_static/panels
+cd homeassistant/components/frontend/www_static/home-assistant-polymer
 npm run clean
-npm run frontend_prod
 
+# Build frontend
+npm run frontend_prod
 cp bower_components/webcomponentsjs/webcomponents-lite.min.js ..
 cp -r build/* ..
 BUILD_DEV=0 node script/gen-service-worker.js
 cp build/service_worker.js ..
-
 cd ..
 
+# Pack frontend
 gzip -f -k -9 *.html *.js ./panels/*.html
+cd ../../../..
 
 # Generate the MD5 hash of the new frontend
-cd ../../../..
 script/fingerprint_frontend.py