Improve how the feedback form works: Add support for public comments to share your experiences of using a tool in practice

[Greenheart]

For more info, see the idea from https://github.com/Greenheart/idg.tools/issues/166, and the following comment https://github.com/Greenheart/idg.tools/issues/166#issuecomment-1331734880.

This is important to allow more ways to co-create the toolkit, and add value for future visitors.

Potential solutions:

• https://commento.io/ seems like a good choice. Need to check how the moderation works though - can multiple people manage it? Also with backups, does it allow simple data exports that can be archived for the future?