Fix dockerignore and improve pre-push hook

Remove some entries in dockerignore that prevented the image from
running properly.
Improve pre-push hook to prompt user to confirm that they want to push
if there are linter warnings.
Add `extract-translation` script to pre-push hook to prevent pushing if the translation files were not updated properly in the client.
Fix eslint warnings.

Change-Id: Id4491c90c182a62c1ec66a300f29f5716ea70491
diff --git a/Dockerfile b/Dockerfile
index 0f6c3cf..2be5031 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -5,7 +5,7 @@
 ENV SECRET_KEY_BASE=test123
 
 # Install dependencies
-RUN apt-get update && apt-get install -y \
+RUN apt-get update && apt-get install -y --no-install-recommends \
     lldb \
     liblldb-dev