Revert "Migrate to JSON i18n"

Causes "PHP Notice:  Undefined index: en in /data/project/apache/common-local/php-master/extensions/MwEmbedSupport/MwEmbedResourceManager.php on line 49"

This reverts commit 11ee237f28910bc028047f9b23c9ba4b8cb241b8.

Change-Id: Ia3205d14372ebe833108d196ee32650d393f87f3
Merge "Revert "Migrate to JSON i18n""