Replace web3 by ethers.js in faucet

[markspanbroek]

The faucet currently uses the web3.js library to transfer ether. Since we're moving away from web3 it would be nice to refactor the faucet to drop web3 in favour of ethers.js.

An attempt has been made in the 'faucet-replace-web3-by-ether' branch, but although the tests pass, the faucet itself doesn't work when connecting to ganache. It throws an error indicating that the TCP connection to ganache is refused.

Reproducing the error:

• checkout the 'faucet-replace-web3-by-ether' branch
• start the demo app: cd workspaces/demo-app && yarn start:all
• open the demo app at http://localhost:3000
• switch to the 'Executing Contracts' demo
• press 'increase by 5'
• scan QR code with the Cogito app
• see the connection refused error appear in the terminal where the demo app was started