Make implicit conversion operators explicit for NodeId/ExpandedNodeId #3548
Description
uint and Guid are still implicitly converable to NodeId/ExpandedNodeId. This can create situations where a uint or Guid is assigned accidently to said types without specifying a namespace index. Since users will likely work mostly with their own namespace, we should make these conversion operators Explicit.
Originally posted by @marcschier in #3534 (comment)