Refactor extension to webpack

This change is the biggest in the history of the project. The entire
project has been refactored so it is built with webpack.

This involves:
- Creating webpack and npm config files.
- Fixing some bugs in the code due to the fact that webpack uses strict
mode.
- Merging some pieces of code which were shared throughout the codebase
(not exhaustive, more work should be done in this direction).
- Splitting the console_inject.js file into separate files (it had 1000+
lines).
- Adapting all the build-related files (Makefile, bash scripts, etc.)
- Changing the docs to explain the new build process.
- Changing the Zuul playbook/roles to adapt to the new build process.

Change-Id: I16476d47825461c3a318b3f1a1eddb06b2df2e89
diff --git a/tools/release.bash b/tools/release.bash
new file mode 100644
index 0000000..338d9e1
--- /dev/null
+++ b/tools/release.bash
@@ -0,0 +1,107 @@
+#!/bin/bash
+#
+# Generate release files (ZIP archives of the extension source code).
+#
+# Precondition: webpack has already built the extension.
+
+# Prints help text
+function usage() {
+  cat <<END
+
+  Usage: $progname [--channel CHANNEL --browser BROWSER]
+
+  optional arguments:
+    -h, --help     show this help message and exit
+    -c, --channel  indicates the channel of the release. Can be "beta"
+                   or "stable". Defaults to "stable".
+    -b, --browser  indicates the target browser for the release. Can be
+                   "chromium", "gecko" or "chromium_mv3".
+                   Defaults to "chromium".
+
+END
+}
+
+# Updates manifest.json field
+function set_manifest_field() {
+  sed -i -E "s/\"$1\": \"[^\"]*\"/\"$1\": \"$2\"/" dist/$browser/manifest.json
+}
+
+# Get options
+opts=$(getopt -l "help,channel:,browser:" -o "hc:b:" -n "$progname" -- "$@")
+eval set -- "$opts"
+
+channel=stable
+browser=chromium
+folder=null
+
+while true; do
+  case "$1" in
+    -h | --help)
+      usage
+      exit
+      ;;
+    -c | --channel)
+      channel="$2"
+      shift 2
+      ;;
+    -b | --browser)
+      browser="$2"
+      shift 2
+      ;;
+    *) break ;;
+  esac
+done
+
+if [[ $channel != "stable" && $channel != "beta" ]]; then
+  echo "channel parameter value is incorrect." >&2
+  usage
+  exit
+fi
+
+if [[ $browser != "chromium" && $browser != "gecko" &&
+      $browser != "chromium_mv3" ]]; then
+  echo "browser parameter value is incorrect." >&2
+  usage
+  exit
+fi
+
+echo "Started building release..."
+
+# This is the version name which git gives us
+version=$(git describe --always --tags --dirty)
+
+# If the version name contains a hyphen then it isn't a release
+# version. This is also the case if it doesn't start with a "v".
+if [[ $version == *"-"* || $version != "v"* ]]; then
+  # As it isn't a release version, setting version number to 0 so it
+  # cannot be uploaded to the Chrome Web Store
+  set_manifest_field "version" "0"
+  set_manifest_field "version_name" "$version-$channel"
+else
+  # It is a release version, set the version fields accordingly.
+  set_manifest_field "version" "${version:1}"
+  set_manifest_field "version_name" "${version:1}-$channel"
+fi
+
+if [[ $channel == "beta" ]]; then
+  # Change manifest.json to label the release as beta
+  set_manifest_field "name" "__MSG_appNameBeta__"
+
+  if [[ $browser == "gecko" ]]; then
+    # Change the extension ID
+    set_manifest_field "id" "twpowertools+beta@avm99963.com"
+  fi
+else
+  if [[ $browser == "gecko" ]]; then
+    set_manifest_field "name" "__MSG_appNameGecko__"
+  fi
+fi
+
+# Create ZIP file for upload to the Chrome Web Store
+mkdir -p out
+rm -rf out/twpowertools-$version-$browser-$channel.zip
+(cd dist/$browser &&
+  zip -rq ../../out/twpowertools-$version-$browser-$channel.zip * -x "*/.git*" \
+  -x "*/\.DS_Store" -x "*/OWNERS")
+
+echo "Done!"