Improve Device Renderer destruction

[pgivel]

Description

This PR improves Device Renderer destruction, in hopes of it getting garbage-collected when we don't need it anymore.

Most event handlers lambda were moved to class methods, so that they could be properly removed, and most plugins had destroy functions added, and called in the Device Renderer destroy.

Type of change

• [ ] Bug fix (non-breaking change which fixes an issue)
• [x] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• [x] I've read & comply with the contributing guidelines
• [x] I have tested my code for new features & regressions on both mobile & desktop devices, using the latest version of major browsers.
• [x] I have made corresponding changes to the documentation (README.md).
• [x] I've checked my modifications for any breaking changes.