feat(cosmos-kit, docs): apply prax extension

[VanishMax]

Integrates prax-extension package into cosmos-kit and adds documentation about the package.

[pyramation]

Hi there! Thanks so much for your work on this PR - we really appreciate your contribution :)

After reviewing the changes, we think it might be best to hold off on merging this for now. The PR introduces quite a few libraries that aren't typically included in Cosmos chains by default. While we're excited about the possibilities, we'd love to collaborate on a plan for integrating these components in a way that aligns with our current structure.

For example, elements like buf build, the Penumbra protos, and similar tools are usually added as options in Cosmos Kit by developers based on their specific needs. This approach helps keep the bundle size as minimal as possible.

Before we make prax-extension available by default in this way, we'd need to work on its structure a bit more. Let's take this over to Slack and keep this in draft state for now :)