tailcfg, util/deephash: add DataPlaneAuditLogID to Node and DomainDataPlaneAuditLogID to MapResponse

We're adding two log IDs to facilitate data-plane audit logging: a node-specific
log ID, and a domain-specific log ID.

Updated util/deephash/deephash_test.go with revised expectations for tailcfg.Node.

Updates https://github.com/tailscale/corp/issues/6991

Signed-off-by: Aaron Klotz <aaron@tailscale.com>

tailcfg/tailcfg_clone.go

@@ -95,6 +95,7 @@ var _NodeCloneNeedsRegeneration = Node(struct {
 	ComputedName            string
 	computedHostIfDifferent string
 	ComputedNameWithHost    string
+	DataPlaneAuditLogID     string
 }{})
 
 // Clone makes a deep copy of Hostinfo.