Move default socket properties to update system

Created by: Durman

Addressed problem description

Initially it was conceived as performance improvement but on my test trees I was able to measure an improvement only with trees of 400+ nodes and only of 1%. Probably the improvement can be more significant on bigger lightweight trees. But also the new feature is introduced:

We have sockets which store their default properties in their nodes. It involves using of socket.node api wich, as were said, takes O(len(tree.nodes)) time. Ve have alternative of storing default values in socket itself but switch all nodes to it will take a lot of time and most likely it will break work of Sverchok extensions.

The solution is to move extracting of default values to the update system to which fo find a socket owner is not a problem. Update system can read default value and put it into socket_data cache where it can found by the node. So the socket_data module will keep not only generated by the nodes data but also and default values now.

I have doubts of adding extra complexity to data management but it seems the less sockets and nodes use is_linked API the better.

Closes #4475

Preflight checklist

• Code changes complete.
• Code documentation complete.
• Ready for merge.