Design a better trace for what happened in the framework #348

Currently, we only have the list of messages (WiseAgentMessage) sent in each context.
Most likely, we need much more information. Ideally, a dump of the context would be ideal, along with the current list of messages (+ timestamp for sent/processed, which may be added directly to WiseAgentMessage). The WiseAgentMessage should probably also contain the destination (currently contains only the sender). Having both sender/destination makes redundant the list of participants (at least from a trace perspective)

The main point, anyway, is to decide how we want to represent contexts (see discussion #325) and most likely reflect this in the trace. As soon as we will have got a decision for #325 I can work on the trace, making a concrete proposal to discuss on to of it.