[plugin.audio.radiofrance] v1.1.1 Robustify and speedup

[bateast]

Move to a class based design
Use multithreading to speedup parsing
Deal with json parsing exception to manage parsing issues.

Checklist:

• My code follows the add-on rules and piracy stance of this project.
• I have read the CONTRIBUTING document
• Each add-on submission should be a single commit with using the following style: [plugin.video.foo] v1.0.0

[basrieter]

This PR contains some mix-up due to rebasing. Please do a proper rebase and update the PR with a single commit from your own repo.

Currently it also contains some plugin.video.dumpert stuff.

[basrieter]

Please either fix issues in this PR or close it.