* Moved 'addressing' to nymsphinx + slightly better API + tests
* Replaced all usages of above in the project
* Removed 'split_and_encapsulate_message' from chunking API to get rid of circular dependency + to prefer usage of TopologyAccessor
* changes in Cargo.lock
* formatting
Basic support for message chunking and reconstruction. It's now possible to take arbitrarily-sized input and send it through the mixnet. The sending Nym client will automatically chunk the input into Sphinx packets, and the receiving Nym client will then reconstruct the message at the other end.