Migrate off of `eth-*` and `ethjs-*` packages

[mcmire]

According to the page for the ethjs org, the ethjs packages are no longer maintained and ethers is suggested instead. The ethjs repo is also archived. Finally, it is a bit of a pain to even work with these packages, as the main file for them (again, see ethjs) seems to link to the uncompiled version the library rather than the compiled version, and for the current version of ethjs-query that we are using, this code contains Babel-specific code. We can upgrade to the latest versions of these packages, of course, and that would probably help us a little bit, but the point still stands that it will end up being a waste of time to keep using these libraries. They are right to suggest Ethers, because Ethers seems to be the best-maintained library when it comes to interactions with Ethereum (it also includes TypeScript types for all of its parts). We should consider switching fully to Ethers.

[desi]

There are 2 technical proposals and the issues created for those should replace this. Closing.