Add fix for test coverage and integrate coverage in the CI

[The-3D]

It's currently impossible to run test coverage as the compilation of the protocol contracts currently fails without optimizations enabled. There is a proposed solution here ethereum/solidity#10354.
Implement the fix and activate the code coverage for the protocol in the CI

[JasoonS]

BTW, I got it fixed and working here: https://www.npmjs.com/package/@float-capital/solidity-coverage

Simply install the package and change the following in your hardhat.config.js:

-require("solidity-coverage");
+require("@float-capital/solidity-coverage");

Hopefully will be up-streamed soon 👍