migrate most of the Gradle API in IntelliJPlugin.kt to use the Gradle Kotlin DSL extensions

[aSemy]

Pull Request Details

Improve compatibility with Gradle API by using Gradle Kotlin DSL helper extensions

Description

migrate most of the Gradle API in IntelliJPlugin.kt to use the Gradle Kotlin DSL extensions

Related Issue

#1114

Motivation and Context

Improve compatibility with Gradle API by using Gradle Kotlin DSL helper extensions

How Has This Been Tested

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• I have read the CONTRIBUTING document.
• My code follows the code style of this project. - I don't know, because the code style isn't documented Document code style #1116
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have included my change in the CHANGELOG.
• I have added tests to cover my changes.
• All new and existing tests passed.

[hsz]

Magic!