e2e tests with TLS

[dakom]

Our e2e tests would take a lot of gas to test against real testnets/mainnets, but we can at least catch errors like #1022 earlier on by testing against a wss and https proxy

Starting the proxy should be doable via just commands so we can easily do it both for local dev and in CI

stunnel is probably the simplest since this is just for tests and has the least moving parts, but caddy or other options are viable too and may be necessary for both websocket and https simultaneously over the same port.