Add translators to the credits dialog

- Add tooling at //tools/i18n to generate the file with the information
  about the translators: //src/json/i18n-credits.json.
- Change credits.json to remove an entry from a translator, who is now
  mentioned in the i18n credits.
- Change Makefile and release.bash to incorporate the i18n credit
  generation in the process of building the extension.
- Change options page to accommodate the translators section.

Change-Id: I7f3991f9c456c381832f4a7bebdfc5581ef9e4be
diff --git a/generatei18nCredits.bash b/generatei18nCredits.bash
new file mode 100644
index 0000000..38da15b
--- /dev/null
+++ b/generatei18nCredits.bash
@@ -0,0 +1,2 @@
+(cd tools/i18n && go run generate-i18n-credits.go)