[bug 896137] Remove l10n calls

This template is currently just filler. We don't want localizers to
waste time translating these strings. Implementing the template is the
subject of another bug.
[bug 896137] Fix badger migration

* remove BEGIN/COMMIT
* add content type hoo-hah
[bug 896137] Fix kbadge test stuff

* nix incorrect comment
* fix with_save kwarg
Update migration-building-related docs