Change web3 connection method

[andytudhope]

While we are removing unnecessary libraries and generally cleaning up how we use Embark, let's make sure we migrate to the latest use of web3 to avoid this error message in the web console:

MetaMask no longer injects web3. For details, see: https://docs.metamask.io/guide/provider-migration.html#replacing-window-web3

It seems that MM also prefer the web3_getAccounts method over ethereum.enable() - this is worth looking further into (and can be seen in the console when you submit a DApp and are asked to connect your wallet).

cc @richard-ramos @RyRy79261