add Korean locales

[gimapei]

• Bugfix (non-breaking change which fixes an issue)
• [ x ] New feature (non-breaking change which adds functionality)

It's just locale file for Korean

Proposed changes

Checklist

• [ x ] I have read the contribution guidelines
• For non-bugfix PRs, I have discussed this change on the mailing list/slack team.
• [ x ] I have run grunt to verify the unit tests pass
• I have added suitable unit tests to cover the new/changed functionality

[jsf-clabot]

All committers have signed the CLA.

[gimapei]

hello, I am Joe form korea,
I added language files for Korean.
I think it will help many Koreans.

thanks. bye

[coveralls]

Coverage remained the same at 76.466% when pulling a252514 on gimapei:master into a6ef755 on node-red:master.

[knolleary]

Hi, thanks for this.

Please can you use the dev branch as that is the next release and contains a few changes to the messages.

We would also like this to be reviewed by the community before accepting as we cannot verify the translations ourselves.

[gimapei]

sure. I can work for dev branch.
it take's some time

[knolleary]

Closing in preference to #2004