Use godoc/gnodoc for displaying docs on p/demo packages

[leohhhn]

Description

As we discussed in a call today, we should keep on-chain package docs within package/realm code itself. This way, documentation/usage instructions for packages can be on-chain, and displayed with a version of godoc, while the Official Documentation can document Gno.land concepts, references, etc more generally.

I suggest we remove package-specific docs from the Official docs, such as AVL tree docs, and simply point users to use godoc/onchain comments to learn how a package works. We can leave the Packages/Realms page to document the ideas and concepts, possibly include a few examples, and point people to the actual on-chain code.

This will:

• Help with transparency
• Minimize Official docs footprint and maintenance efforts
• Force developers to write godoc instructions/docs within their code.

cc @thehowl @moul

[thehowl]

#522