Extend extensions readme generator

[migmartri]

#191 added support for a generator that keeps extension Readme files up to date with their input schema information.

We'd like to extend this generator to inject additional metadata such as description id subscribed inputs and so on.

@danlishka had some suggestions on the format #191 (comment)

[danlishka]

Add supported materials section as well.

https://github.com/chainloop-dev/chainloop/pull/211/files#r1245729281