Discovery takes sometimes too long #158
Description
Sometimes discovery takes a couple of seconds which makes Reflection feel "slow" and unresponsive. This can happen in situations where the random walker is going through a list of "stale" nodes (peers which have been online recently but are not anymore and we find out about this for the first time) before it "hits" the right ones.
The reason behind are the heuristics and algorithm of p2panda's discovery strategy which needs more tuning. One approach is to "eagerly" already start discovery sessions without waiting for the last to finish.