Versioning of UI and grpc-agent for passing version (#324)

Send Desktop UI client version as user-agent to daemon

This is sent on every login request to the management

Parse the GRPC context on the system package and 
retrieves the user-agent

Management receives the new UIVersion field and 
store in the Peer's system meta

client/cmd/version.go

@@ -11,7 +11,7 @@ var (
 		Short: "prints Netbird version",
 		Run: func(cmd *cobra.Command, args []string) {
 			cmd.SetOut(cmd.OutOrStdout())
-			cmd.Println(system.WiretrusteeVersion())
+			cmd.Println(system.NetbirdVersion())
 		},
 	}
 )