Migrate to @api3/contracts

[hiletmis]

Closes #2031

[dcroote]

Disregard the failing docker build CI- this is expected until there is a changeset merged to the master branch. This happens when there aren't yet changessets after a release (which is true now because this would be the first commit since v0.15). (#1585)

[hiletmis]

Thanks for the notice @dcroote.I had to add --ignore-engines to check if there is an additional problem to strict engines rule. Because @api3/contracts requires node to be >=20.17.9 for now and yet it will be >=22.18.0 on next release.

[Siegrift]

I leave this to @dcroote

[dcroote]

Addressing the e2e CI failure in #2041

[hiletmis]

contracts package is not bumped anyway. Is there any specific reason not to use integrated hardhat-config and abandon @api3/contracts package

[dcroote]

The use of CHAINS here is perhaps the only unique use of the @api3/chains / @api3/contracts package, but if you think hardhat-config could suffice I think fewer dependencies would be better