Add KDL support

[sed-i]

Is your feature request related to a problem? Please describe.
When setting up my dev env, I'd like to use dasel to update Zellij config entries in .config/zellij/config.kdl, but KDL isn't supported yet.

Describe the solution you'd like
The kdl-go lib is listed on https://kdl.dev/

Describe alternatives you've considered
Dedicated kdl editor, but I'd rather have one tool - dasel - for all document types.

[TomWright]

Thanks for the request.

I'll do some investigation into the matter, but the given library looks promising.