Highlight differences & strengths of echidna vs. other fuzzers (like foundry)

[0xPhaze]

Some things that could be covered:

• ease-of-use/difficulty in setting up the framework
• compatibility with solidity versions
• framework's areas of focus (echidna is e.g. better at property/invariant-testing whereas foundry is great for scripting/deployments & unit-tests)
• create a baseline of different fuzz/invariant tests that should be found and benchmark these