feat: KTX module

[SubSide]

Prerequisites for Code Changes

• This pull request follows the code style of the project
• I have tested this feature

...

Additional Information

This will add a few kotlin convenience extension functions in a separate library so it can be thrown in if the person wants it.

[PhilippHeuer]

Thanks a lot for creating this PR / working on a kotlin module :)

I left a few general comments, but should find the time to really review it in the next few days.

[stachu540]

I can at least add one more thing. For documentation please use Dokka. And generate javadoc using dokkaJavadoc task. About aggregate them... we do not have a clue to add them to website. Maybe in the future? Who knows?

[iProdigy]

Thanks for getting started on this!

[stachu540]

I'd add some suggested changes, if @iProdigy / @PhilippHeuer have time to check. :)

[SubSide]

We're not using it, so there is no reason to include it.

[stachu540]

so there is no reason to set kotlinOptions.jvmTarget in KotlinCompile tasks

[iProdigy]

don't need to explicitly add stdlib: https://kotlinlang.org/docs/gradle.html#dependency-on-the-standard-library

we could specify jvmTarget (but it already defaults to 1.8): https://kotlinlang.org/docs/gradle.html#attributes-specific-to-jvm

[stachu540]

Last thing todo is rename:
kotlin/src/main/java/com/github/twitch4j/kotlin/chat/ChatKtx.kt -> kotlin/src/main/java/com/github/twitch4j/kotlin/chat/Chat.kt
kotlin/src/main/java/com/github/twitch4j/kotlin/main/HystrixKtx.kt -> kotlin/src/main/java/com/github/twitch4j/kotlin/api/Hystrix.kt
kotlin/src/test/java/com/github/twitch4j/kotlin/chat/ChatKtxTest.kt -> kotlin/src/test/java/com/github/twitch4j/kotlin/chat/ChatTest.kt

[stachu540]

LGTM

[SubSide]

👀

[iProdigy]

Thanks for your contribution & apologies for the merge delay