Use data radius to prioritize requests for recursiveFindContent

[kdeme]

When starting a recursiveFindContent request, it first looks up the closest nodes in the local routing table.
Then continiously trying to contact closer nodes.

However, data radius of the nodes also plays a role here. We could prioritize on nodes for which the data radius actually falls in the target range (if we know the data radius of the node). It is however to be seen if this added complexity is worth it in terms of amount of nodes we need to contact on average before we find the content.