add missing guides

[radkomih]

Create step-by-step guides on how to:

• Add a new module

  • implement a new module
  • import and configure it within the runtime
  • build the runtime
  • start a network and test it using the Polkadot/Substrate portal

• Modify Configuration parameters

  • switch the configuration of a given module. Example: Changing Public Keys from sr25519 to ecdsa