WS2P : send details about the WS2P type in head message

We prepare upstream the nodes to accept this new format: https://github.com/duniter/duniter/commit/b3100e4bbaa7174bc35f0a99e33c9d308bac7f37

We have 4 types of WS2P Private:
CA : clear all
TM : tor mixed
TA : tor all
TS : tor strict

And two types of WS2P Public :
C clear endpoint
T tor endpoint

The WS2P Private is prefixed with an O and the ws2p public with an I, so the classic nodes will be of type WS2POCAIC.

The goal is to allow a special node that will archive its heads (such as g1-monit for example) to make statistics on the distribution of WS2p node types on the network.