This is to avoid getting these failing CI tasks where adding a PR to the
board fails when it was already added before (happens when pushing into
an existing PR).
This commit migrates the repo to our foundry template, which ensures we
have consistent tooling across smart contract repositories that are
maintained by Vac.
This removes all hardhat related files and workflows and replaces them
with more perfomant foundry workflows.
It also sets up tests, CI and linting.