[Docs] Add Korean localization for documentation

[umyunsang]

Summary

This PR adds Korean localization for SeaTunnel documentation.

Changes

• Added complete Korean translation in docs/ko/ directory
• Translated core documentation including:
  • Quick start guides (Flink, Spark, SeaTunnel Engine)
  • Docker and Kubernetes deployment guides
  • Connector documentation (V2)
  • Transform documentation
  • FAQ and command references

Files Added

• docs/ko/ - Korean documentation directory
• All markdown files translated to Korean

Localization Details

This PR introduces Korean language support for SeaTunnel documentation,
making it more accessible to Korean-speaking users and contributors.

[davidzollo]

Thank you for your PR,
It's a good beginning. I'm a little worried because this work needs two more contributors to maintain the Korean work. It's not an easy task to maintain it for a long time. Can you find more contributors to do it?

[dybyte]

Hi @davidzollo , I can help by reviewing the Korean documentation PR and providing feedback.

[dybyte]

However, this PR does not translate all of the documentation. Many of the docs are still written in English.

[MyeoungDev]

Hi @davidzollo ,
As a Korean user who has been actively using SeaTunnel,
I'm very interested in contributing to the Korean documentation PR.
Please consider my active participation.

[davidzollo]

Thank you all, thank you very much for your contributions to help SeaTunnel develop better and better.
I'm a little concerned that a lot of contributors don't know Korean at all, so they can't provide Korean documentation when submitting PRs. I think English documentation is much more useful and easier to maintain for contributors.
If you are interested, how about writing several practical articles about Apache SeaTunnel in Korean?

[Hisoka-X]

Many of the docs are still written in English.

We should only keep the doc which not english. Just like chinese.

[dybyte]

I'm a little concerned that a lot of contributors don't know Korean at all, so they can't provide Korean documentation when submitting PRs. I think English documentation is much more useful and easier to maintain for contributors.
If you are interested, how about writing several practical articles about Apache SeaTunnel in Korean?

I also think it would be difficult to maintain the Korean documentation since there are few contributors who are fluent in Korean. Is there anyone who would be interested in writing practical articles?