Translations: Add Localisation Support for `gettext`

[CakeVR]

Is your feature request related to a problem? Please describe.
Godot supports gettext, it's a very popular tool for localisation.
See here: https://docs.godotengine.org/en/stable/tutorials/i18n/localization_using_gettext.html

Describe the solution you'd like
Add support of gettext, just like CSV has.

This issue is potentially a duplicate or subset of: https://github.com/coppolaemilio/dialogic/issues/1493