Update readme to provide Kotlin usage

[chakibchemso]

• Added Kotlin usage.
• Fixed some typos I found.

Java is old, glory to Kotlin! ;)

[polymonster]

Would you be able to provide a working example of Kotlin usage like there is for Java/JNI and C++. We can also hook it up to the automated GitHub actions.

Would be nice to have working code in addition to just info in the readme if possible.

[chakibchemso]

Hi, unfortunately I can't since I don't have experience with android development. I merely made the changes from a general programming knowledge. So, I'd probably leave this for someone else who's expert in the field. or I might end up doing it if I get the chance to work with android studio in the future. For now, I'm focusing on the core of my game engine and deploying for windows.