This removes the dependency on OpenSSL for the interaction tests, by providing a pure-Python
toy implementation of secp256k1.
Github-Pull: #15826
Rebased-From: 8c7b9324ca3f3ffb178bea56a96ea23f7e0383cb
fa5587fe71 qa: wait_for_verack by default (MarcoFalke)
Pull request description:
This removes the need to do so manually every time a connection is added.
Tree-SHA512: a46c92cb4df41e30778b42b9fd3dcbd8d2d82aa7503d1213cb1c1165034f648d8caee01c292e2d87d05b0f71696996eef5be8a753f35ab49e5f66b0e3bf29f21