use XDG standards for cache dir, and use Gradle Providers API more

[aSemy]

Pull Request Details

Tries to follow XDG standards.

Description

• Use XDG cache home if it's available
• else use $USER_HOME/.cache
• I changed the system-temp dir to the task temp-dir. I suspect that user.home is only going to be unavailable on CI, so using the task dir is going to work the same way.
• I updated the logic to make more use of the Gradle Provider API (Improve compatibility with the Gradle API #1114)

Related Issue

fixes: #1118

related: #1114

Motivation and Context

• better compatibility with XDG standards
• Cleaner home dir for users
• Better use of the Gradle Provider API

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 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.