Change docs/android-installation.md to include Kotlin guide

[savaliyap]

Bug report

• [x] I've checked the example to reproduce the issue.

• Reproduced on:

  • [x] Android
  • [ ] iOS

Description

Change docs/android-installation.md to include Kotlin guide as well, as newer React native versions use MainActivity.kt also the guide uses older gradle syntax

Steps to Reproduce

Versions

- Callkeep: Latest
- React Native: Latest(EXPO)
- iOS:
- Android:
- Phone model: 

Logs

NA

[mritul]

has this been solved ? It would be great if there was a Kotlin guide too

[fvcoder]

x2