Add a wavpack default configuration to the badfiles plugin

[Serranya]

Description

Wavpack files can now be verified by the badfiles plugin without addition configuration by the user.

• [x] Documentation. (If you've added a new command-line flag, for example, find the appropriate page under docs/ to describe it.)
• [x] Changelog. (Add an entry to docs/changelog.rst to the bottom of one of the lists near the top of the document.)
• [x] ~Tests. (Very much encouraged but not strictly required.)~

[stale[bot]]

Is this still relevant? If so, what is blocking it? Is there anything you can do to help move it forward?

This pull request has been automatically marked as stale because it has not had recent activity. It will be closed if no further activity occurs. Thank you for your contributions.

[JOJ0]

looks straightforward but what is wavpack actually?