Malus: improvements in dispute ancestor and suggest garbage candidate implementation

[sandreim]

First step(s), see #4874

• Implemented fake validation as a component that is reused in dispute_valid_candidate.rs and suggest garbage candidate.rs.
• The fake validation is configurable to report valid candidates as invalid or report malicious candidates as valid to the backing/approval subsystems.
• Implemented suggest garbage candidate using the draft from Malus: Implement storing invalid chunks #4711 as a starting point

These two malus nemesis implementations will be used in the parachain zombienet test suite:

• malicious nodes initiate disputes of valid candidates (dispute_valid_candidate)
• honest nodes initiate disputes of invalid candidates backed by malicious nodes

I attached some screenshots to show how suggest garbage candidate malus nodes perform in a zombienet test. The first image shows disputes for malicious candidates concluding as valid and the inclusion blocks being finalized. The next two show disputes concluding as invalid and chain reversions.

This shows up on honest validators when they run the PVF with a malicious PoV:

2022-03-30 14:02:30 panicked at 'invalid block data format.: Error', /home/sandreim/polkadot/parachain/test-parachains/undying/src/wasm_[validation.rs:30](http://validation.rs:30/):58

[drahnr]

A few nits, Valid should be implemented before merging. Besides that - 👍

[eskimor]

First pass, got half way through. Remaining review coming soon.

[eskimor]

Looks good overall - code is clean and relatively easy to follow as well.

[sandreim]

bot merge