chore: use medusa instead of echidna

[0xteddybear]

this PR intends to make the boilerplate follow what we currently are doing for production repositories regarding fuzzing campaings:

• using medusa instead of echidna
• separating handlers and pure property checks by naming convention, while only allowing assertion-mode testing
• discerning between guided and unguided handlers -> usually we do it in separate files, but I figured that's a lot of boilerplate for such a small testsuite, so I'm using different names instead
• use default foundry cheatcodes instead of re-defining them

This does not include a workflow to run medusa in CI, which is currently a WIP on #86

[simon-something]

true by default (avoiding incidents)?

[0xteddybear]

the idea is for the boilerplate to closely resemble what we run in production, and afaik we are disabling property testing in all projects to reduce complexity (2 kinds of tests vs 1) and help avoid mistakes where the property testing mode is disabled down the line and property tests are executed as assertion tests, causing a false negative, since that false negative would be present when the test is initially developed, making it evident

[hexshire]

I think we are not using these.

[0xteddybear]

we are not taking advantage of the various sender addresses in the simple boilerplate example, but they are usually later used in our actor setups for bigger projects, so I lean on leaving them in

what should be the alternative? using only one? I believe medusa wont run if they key is deleted or has an empty array as a value

[hexshire]

I would use just one only if somehow it enhance the performance.

[0xteddybear]

afaik having one vs many doesnt affect performance (as long as having many users doesnt make the domain of possible states grow at a relevant rate, which is not the case for the humble greeter)

[gas1cent]

Agree with the above regarding sender addresses and disabling propertyTesting.