Update Build Section for Agile Coretime

[CrackTheCode016]

With agile coretime, building a parachain (or "task" rather) is much easier, and can be easily included. This will also make much of the information regarding auctions and protocol development in general much more concise. As such, this should be reflected in the Build section, particularly:

• https://wiki.polkadot.network/docs/build-guide
• "Coretime for Parachains" moved here? https://wiki.polkadot.network/docs/build-guide
• Demonstrating the clear path for developing a parachain, purchasing a core, and deploying
• A simple guide even for using the new templates in polkadot-sdk, an end-to-end tutorial for a minimal "task"?

[CrackTheCode016]

Other general notes:

• Include a page on required tooling, Rust, nightly targets, etc
• Include polkadot-sdk-docs a sa primary resource and point to it wherever applicable, and for more on the templates (we shouldn't be covering the templates excessively, just how to use them for the specific purpose of getting started)

[CrackTheCode016]

Concrete Objectives (tentative):

• [ ] Improve/add new Mermaid diagrams for core deployment and processes as needed
• [x] Move existing guides over to build and/or PJS -> #5811
• [ ] Introduce a new "Getting Started with Coretime" section, which introduces an easy, minimal path to what developing for a core looks like -> #5811
• [ ] "Getting Started with Coretime" should include:
  • [ ] Tooling and dependency installation
  • [ ] An overview of the various repositories and structure of polkadot-sdk, which is only a high-level explanation. Any other details are to be directed to polkadot-sdk-docs
  • [ ] A template overview, again, high level
  • [ ] Direct to a basic guide for compiling, interacting with, and going from code -> core deployment

"Getting Started with Coretime" as a section will not be long, nor will it attempt to extensively document Polkadot in a comprehensive manner, but is more a "how to" which uses other parts of the Wiki, i.e., Coretime Marketplaces to easily guide those completely and utterly new.