Add HTML distribution

[yuripourre]

Maybe use GWT:
https://github.com/yuripourre-forks/gwt-awt

[yuripourre]

One approach would be using bytecoder

• Update Event(bytecoder) to include getType (and what else is needed to port gwt).
• Test it using unit tests.
• Port DefaultGwtInput to gdx-backend-bytecoder

Extending JS classes:
https://github.com/mirkosertic/Bytecoder/blob/master/manual/content/chapter-1/page-1-g.md

Tests Explained:
https://mirkosertic.github.io/Bytecoder/chapter-1/page-1-e/

Kotlin example:
https://github.com/mirkosertic/Bytecoder/blob/master/core/src/test/kotlin/de/mirkosertic/bytecoder/core/OpaqueReferenceKotlinTest.kt