Added transaction API for Monolith (bug 920069)
Fix flaky test mkt.developers.tests.test_forms.TestAppVersionForm.test_post_publish

(apparently app_factory and 'created' don't play nice together,
 but it seems to be reliable when used in the version kw, and
 that's all we need here)
Partially revert changes made to files.tests.test_models in aa43c6ba98ee0fa5154c90ad8610e4a4877f8298

The test was right before, we just needed to set the return value of
the mock earlier.
Commit from Mozilla Verbatim by user jasnapaka@jasnapaka.com.: 4947 of 5474 strings translated (5 fuzzy).
Remove old in-app code and old stats (bug 865134)