Docs: Improved Structure for "adding packages" to help contributors find information

[prince-chrismc]

This has been a long standing short coming that make it difficult for new contributors to learn some of the finer details and costs time on the reviewers to help pull requests get merged - and less important but notably the build resources are not insignificant when dozens of commits are pushed trying to correct issues.

🔎 Preview of the direction: https://github.com/conan-io/conan-center-index/compare/master...prince-chrismc:conan-center-index:docs/seperate-by-method?expand=1

Proposed Structures

• Developing recipes locally docs: Document working locally + Conan 2.0 commands #13102
  - This will be the single location for all the commands you need to contribute to CCI
  - One reference package for everything (fmt was picked since it has all the supported configurations of c3i)
• Dedicated "adding packages" folder docs: Create a subfolder for "adding packages" #13736
• Break down content by methods (see below)
• New content for missing section and 2.0 changes

Break down content by

break down methods into their own files (there will be some grouping based on size like "configure, config_options, and validate" would be an example)

• one file for general "files and folders" which lists a very high level of files and what they contain. docs: split out files and folders and the last few attributes #15004
• packaging policy docs: split some policies by the implicated method #14211
• patching policy docs: update picking sources and unify with patching rules #14377
• reviewing Docs: split up reviewing into new file sections #14491
• dependencies docs: add working with dependencies to give a lot more guidance #14833
• readme docs: split out files and folders and the last few attributes #15004

Possible Future Work

• Some good suggestions in docs: split some policies by the implicated method #14211 for "build and package"
• There are a lot of docs that could be moved to the main docs.conan.io side of things that are not specific to ConanCenterIndex

Notable changes

• FAQs and Error Knowledge will point to the new folder and serve to direct people to the "how" answer... the why might stay (TBD how it unfolds)
• everything about "code in the recipes/ should be in this new section

Similar efforts

The main Conan docs have gotten the same treatment