virtcontainers: Rename the Network structure fields and methods

We are converting the Network structure into an interface, so that
different host OSes can have different networking implementations for
Kata.
One step into that direction is to rename all the Network structure
fields and methods to something that is less Linux networking namespace
specific. This will make the Network interface naming consistent.

Signed-off-by: Samuel Ortiz <s.ortiz@apple.com>

src/runtime/virtcontainers/persist/api/config.go

@@ -223,9 +223,9 @@ type ShimConfig struct {
 
 // NetworkConfig is the network configuration related to a network.
 type NetworkConfig struct {
-	NetNSPath         string
-	NetNsCreated      bool
-	DisableNewNetNs   bool
+	NetworkID         string
+	NetworkCreated    bool
+	DisableNewNetwork bool
 	InterworkingModel int
 }