Ensure feature parity with py-ipv8

[dsluijk]

As we want this to be fully compatible with the existing py-ipv8 application. To ensure it is easier in the future to look up how the application works, it should be documented in ipv8-docs

• Add feature parity.
• Add an simple example.
• Document how to implement the IPv8 application.

[jdonszelmann]

help wanted? no worries

[NULLx76]

I'll look and maybe do something, no promises though