Refactor instructions for submitting staged recipes

### Where should the content be added?

https://conda-forge.org/docs/maintainer/adding_pkgs/

### What should be added?

We should refactor the existing guide, so that it is targeted for users who are new to the staged recipe review process. Right now the [adding_pkgs](https://conda-forge.org/docs/maintainer/adding_pkgs/) is long and difficult to read. To make things more digestible for our users, we should instead break this up into multiple smaller guides specifically targeted at what they want to do (e.g. "I want to add a new Python package", "I want to add C++ header library package" or "I want to add a Rust binary package").

Things to consider while going about this implementation:
1. Make a simplified guide for the most used paths (python and python-c); these should appear at the top
2. Add pages stating our review standards for packages (e.g. what makes a good python package? what makes a good c-cpp package?); right now a lot of this lives inside the heads of our reviewers and it needs to be written down somewhere so that we all have a point of reference during our reviews; this also helps train new reviewers.
3. Don't just write the guide; follow the guides yourself and make sure each step makes sense.
4. Make these accessible and easy to find.

### Additional information

One thing worth experimenting with is creating a "wizard" for selecting the type of package you want to submit and then instructions for how to do so. We are using Docusaurus as the documentation backend which means we can easily write little ReactJS components for such things. Not sure if this would actually be useful but could definitely be something fun to experiment around with.