[FEATURE REQUEST] Add catalan dialects ca-ce (central), ca-ba (balearic), ca-va (valencian), ca-nw (northwestern)

[JarbasAl]

Summary

I want to provide translation support for various dialects of Catalan,

ca-ce (central), ca-ba (balearic), ca-va (valencian), ca-nw (northwestern)

In the future i will likely also want to do the same for other language dialects, essentially whenever we put together a translation team of volunteers that speak any dialect natively, we want to add that language

What is the current bug behavior?

Most countries just appear with their 2 letter language code, we can specify our own language code as described in https://github.com/gitlocalize/feedback/issues/86 but we can not use the same language twice

What is the expected correct behavior?

Allow to select the same language again, but specifying a different language code

In my example i would like to select Catalan multiple times for Balearic, Valencian and Northwestern

Possible fixes

Adding these dialects as their own option will solve my immediate problem, and seems to be the solution adopted in previous similar issues https://github.com/gitlocalize/feedback/issues/121

I would prefer the option to select a language multiple times with different language codes as a more viable option long term to allow supporting arbitrary dialects.

Alternatively creating any language we want as suggested in https://github.com/gitlocalize/feedback/issues/111 would also solve this problem