Support TypeChain in deploy and upgrade proxy functions - continuation of work done on #535

[robertmagier]

Continuation of work done on #535 by frimoldi.
See #325 and #1082.

Returns type safe contract types with: deployProxy, deployContract, deployBeaconProxy, and upgradeProxy functions.

This does not apply to deployBeacon, upgradeBeacon, and forceImport since those can return UpgradeableBeacon rather than the implementation contract type.

[ericglau]

Thanks a lot for picking this up and sorry for the late response. This looks great!

I made a few changes as follows:

• deployBeacon and upgradeBeacon should return an UpgradeableBeacon instance, rather than the implementation contract's type. We don't generate detailed TypeChain information for UpgradeableBeacon for now, so I've reverted those to just return Contract.
• forceImport could also return an UpgradeableBeacon if the given address is a beacon. For simplicity, I've reverted that as well so it just returns Contract.
• changed the type definition of ContractTypeOfFactory to be ReturnType<F['attach']> & ReturnType<F['deploy']> since with Ethers v6, attach just returns a BaseContract which does not have the contract's type. But TypeChain provides an override of deploy which gives us the expected type -- this seems to work.

For reference, since our tests in this project uses JS, I created a sample TS project and tested it with these testcases: https://github.com/ericglau/hardhat-upgrades-typechain-tests/blob/main/test/test.ts