[common] Add json schema support

[PrivatePuffin]

Is your feature request related to a problem?

We want to be taken serieusly as a project and currently the lack of json schema on common makes that very weird.

Describe the solution you'd like

We should ensure json schema is added.

Describe alternatives you've considered

Keep the current lacking of json schema, but isn't really an option

Additional context

We cannot have one-man-shows like bjw-s common have json schema and us utterly lacking it. Also would means we can safe a LOT of validation code.

I've read and agree with the following

• [X] I've checked all open and closed issues and my request is not there.
• [X] I've checked all open and closed pull requests and my request is not there.