Use webpack

This change adds webpack as the main tool used while developing the
extension. The extension has been minimally refactored so it works with
webpack, with the intention of refactoring it even further in follow-up
CLs in order to improve the file/folder structure of the project and its
readibility.

Bug: translateselectedtext:5
Change-Id: I89d7422e38fdaf46661c96527c51aa4436ad8056
diff --git a/tools/i18n/generate-i18n-credits.go b/tools/i18n/generate-i18n-credits.go
index 0d75842..e37d419 100644
--- a/tools/i18n/generate-i18n-credits.go
+++ b/tools/i18n/generate-i18n-credits.go
@@ -21,7 +21,7 @@
 const checkAttempts = 5
 const checkWaitTime = 2 * time.Second
 const baseApiURL = "https://api.crowdin.com/api/v2/"
-const i18nCreditsFile = "../../src/json/i18n-credits.json"
+const i18nCreditsFile = "../../src/static/json/i18n-credits.json"
 
 // Contributors who have sent translations before the Crowdin instance
 // was set up: