Add Serbian (Cyrillic & Latin) locales

[rammba]

Hello @shdwmtr, I'm happy to be able to contribute to Steam related project 🚀
I'm currently working on translating the official React documentation to Serbian, but I also contributed with translations to few other open-source projects.

I'm adding two versions of Serbian language, Cyrillic and Latin. Please let me know if I missed to configure or translate something, or if the file naming is incorrect.

[shdwmtr]

Is Serbian even supported by Steam?

[rammba]

Ahh I didn't think about that. On Steam, there is only Serbian language as a Game Support Only. Does Millenium languages need to be in the correlation with the Steam official languages?

[shdwmtr]

Yes, Millennium uses Steam's in built language manager, and if the language isn't apart of Steam's supported languages it won't work.

[rammba]

So language needs to be in the Full Platform Supported Languages list on the Steam? If that's the case I would mention that in the README.
P.S. Is it possible to merge Serbian language files without including them to the Millennium app? I would still try to update these files based on the english.

[shdwmtr]

Yeah it should be mentioned in the README; I've just never had a situation were a language wasn't supported on Steam so I never thought of it.

So language needs to be in the Full Platform Supported Languages list on the Steam?

Yes.

P.S. Is it possible to merge Serbian language files without including them to the Millennium app? I would still try to update these files based on the english.

They wouldn't be usable though?

[rammba]

I've added changes for supported languages in #482.

They wouldn't be usable though?

Yes, but it will be ready if Steam adds Serbian officially at any moment. If you think that's not a good idea, I'm also ok with that. Please close the PR in that case.

[shdwmtr]

I'll leave it here for the time being.