Create getting started guide for nim-libp2p

Done Criteria

• Tutorial introduction: Ping application
• Prerequisites
  • Install Nim
  • Create an empty project
  • Install nim-libp2p
• Setup
  • Create new file "test.nim"
  • Introduce chronos.
  • Import dependencies
    • Import chronos
    • Import libp2p and ping protocol
• libp2p procedures
  • Gentle introduction to nim procedures
  • Create ping procedure
• Run the ping protocol

Why Important

• Showcases how users can get started with nim-libp2p.
• Follows the other getting started tutorials on the docs.

Notes

• Link to status.im tutorials and existing examples.

Start by reading the existing getting-started tutorials in the docs, then compare the status.im tutorials and existing examples mentioned in the issue. Build the guide around a new test.nim Ping application, covering Nim installation, project setup, nim-libp2p and chronos imports, procedures, and running the ping protocol. Done means every checklist item is covered and the tutorial is linked from the docs.