LPS-49438 remove TranslationUpdater iface

Hi Brian,

Sorry, I meant to delete the TranslationUpdater interface in the previous pr. The last commit fixes that.

All these abstractions were created to simplify updating default data translations. PM asked us for a way to make this process simpler, avoiding as much as possible the need to create a hand-crafted upgrade process each time default data translations were added or updated.

The idea was to have a `TranslationUpdater` for each relevant model (DM Document Types, Journal Content Types, etc.) to handle all the gory details on how to update translations for that model. This way, when an UpgradeProcess needs to be written to update some translations, the dev. only has to choose which TranslationUpdaters to execute, making the translation upgrade process a little more declarative.

Anyway, I agree that it is a little early to introduce all these abstractions, as for the moment only DLFileEntryTypes need to be updated.

Thanks!