Improve README.md

[kelson42]

It should better include:

• A badge to latest CI run
• An stub example how to use the library

[kelson42]

Mostly done with #55

@MohitMaliDeveloper Can you please put a simple example in Kotlin how to load a zim file and an article? i have also a question: can this lib be used in a normal java program on linux?

[mgautierfr]

can this lib be used in a normal java program on linux?

Not tested, but I would say mostly.

The only dependency to android is in :
https://github.com/kiwix/java-libkiwix/blob/main/lib/src/main/java/org/kiwix/libkiwix/JNIKiwix.java

But we may have to fix few small things before having a truly java library (compilation, ...)

[MohitMaliFtechiz]

@MohitMaliDeveloper Can you please put a simple example in Kotlin how to load a zim file and an article?

I have made these changes in #60.