Add Simplified Chinese localization

[TerrestrisYE]

• Add Simplified Chinese localization

[JadeOfMaar]

Hey there. Thanks for your contribution. I assume that you may not know this... Each of the 3 OPT mods has its own localization file.

[TerrestrisYE]

Hey there. Thanks for your contribution. I assume that you may not know this... Each of the 3 OPT mods has its own localization file.

Thanks for telling me. :)

[TerrestrisYE]

The simplified Chinese localization are completed without following parts:

• OPT 2.5m I MK22 Cockpit
• OPT 2.5m I-LS AA Cockpit MK I
• OPT 2.5m ISP Shuttle Cockpit Legacy
• OPT JSL MK I Cockpit Legacy
• OPT-W Airbrake Large
• OPT-W Airbrake Small

I didn't find the localizaiton entry for them.

The text of 'OPT RCS Port' seems to be no change after applying localization.