Consolidate strings into common directory

[abrenoch]

To make it easier to use lokalise to handle user contributions to the translations, we should move all the strings to the common directory. Otherwise we would need to manually organize those values every time a translation is added or updated.

We should probably organize the default values and the prefkey* values to a different file as well so they don't get mixed up with the translation strings. Lokalise only supports string values anyway so we would have to store those in a different file regardless,

[abrenoch]

Scratch this. Seems like lokalise can handle this