refactoring ws2p connetion priorities

Definition of a priority level for each key:
by default the level is zero
If the key is a member: +1
If the key is preferred/privileged: +2
If the key is the same as yourself: +4 (for multi-node)

link to #1184 (closed)

mentioned in issue #1203

mentioned in merge request !1208 (closed)

mentioned in commit a36d2892

mentioned in commit 1d251881

mentioned in commit 0345d7e5

changed milestone to %1.6.0

closed

changed the description