Simplify locale: use single struct hierachy with optional fields

[Aras14HD]

Currently Locale is quite unwieldy. If one wants to add a single field, they have to make a new module, copy the struct with the field, add it, copy the struct that is in, change it and so on until Locale. Then they have to add these structs to the helper enums and add the get/set_field macro invocations.

This architecture was chosen to have locale versions. I feel that there is too little benefit in having versions to justify this complexity.

With these changes, that replace the versions with simple optional fields, we save 240 lines in locale.

[tolik518]

The changed lines looked scary before I've seen the changes :D

I'll QA all the open PRs sometime next week as I'm currently in the middle of moving and I don't have internet in my new flat yet.

If something critical happens in my absence, feel free to merge fixes

I'll still lurk here, but only on the phone

[tolik518]

Looks good from what I've seen. After #327 was merged I'll merge this one