removed PhantomJS in favor of ChromeHeadless and upgraded Karma, removed Karma tests from Dockerfile

Dockerfile

@@ -99,15 +99,6 @@ ADD static static
 # Run Webpack
 RUN yarn build
 
-# Run front-end tests
-ARG RUN_TESTS=true
-ENV RUN_TESTS ${RUN_TESTS}
-
-ADD karma.conf.js karma.conf.js
-RUN if [ "$RUN_TESTS" = true ]; then \
-        yarn test; \
-    fi
-
 # Optimize our images
 ADD static/img static/img
 RUN jpegoptim static/img/**/*.jpg
@@ -161,6 +152,9 @@ RUN rm -rf /grunt
 RUN rm package.json yarn.lock
 
 # Run the tests
+ARG RUN_TESTS=true
+ENV RUN_TESTS ${RUN_TESTS}
+
 ENV RUN_ACI_TESTS False
 ADD requirements-tests.txt requirements-tests.txt
 
@@ -168,7 +162,6 @@ RUN if [ "$RUN_TESTS" = true ]; then \
       venv/bin/pip install -r requirements-tests.txt ;\
     fi
 
-
 RUN if [ "$RUN_TESTS" = true ]; then \
       TEST=true PYTHONPATH="." venv/bin/py.test --timeout=7200 --verbose \
                 --show-count -x --color=no ./ && rm -rf /var/tmp/; \