Full Kotlin migration for example project, Gradle plugin update to 7.2, target SDK 32, updated all dependencies

[BharathVishal]

PR Checklist:

• [x] I have tested this extensively and it does not break any existing behavior.

PR Description

• Performed a full conversion of MPChartExample project to Kotlin. Kotlin migration.
• Set target and compile SDK version to API 32.
• Replaced android-maven-gradle-plugin (deprecated) to maven-publish in build.gradle for MPChartLib.
• Upgraded Gradle version to 7.1.1.
• Built project in Android Studio 2021.1.1 Patch 1 (Bumblebee).
• Updated all internal dependencies.
• Upgraded project version to 3.1.1

• This commit changes all existing java files in the example project to Kotlin.

This commit updates the existing project with recent target SDK, kotlin support for example project and other dependency updates which makes the project up to date.