wireproto: use pushkey.encodekey

pushkey: introduce an ``encodekeys`` function This function provides a standardized way to exchange pushkey content over the wire.

bundle2: add more phase movement in the test To test phase exchange with bundle2 we need some phase movement to happen. Appropriate logging is added to track those changes.

bundle2: use non-publishing repo in test If we are going to test usage of bundle for phases exchange, we need some phase movements to be exchanged.