Add API check for official apps support, with verbiage.

* The apps are predicated on use of specific lang project API endpoints.
* To save bandwidth, only return verbiage specific for language.
* Some carriers like verbiage on the web, but not apps.

Change-Id: I588d1edf904e336b95b91793f7f9c450a69873b5
Merge "Add API check for official apps support, with verbiage."