Routemgr error handling (#1073)

In case the route management feature is not supported 
then do not create unnecessary firewall and manager instances. 
This can happen if the nftables nor iptables is not available on the host OS.

- Move the error handling to upper layer
- Remove fake, useless implementations of interfaces
- Update go-iptables because In Docker the old version can not 
determine well the path of executable file
- update lib to 0.70

client/internal/routemanager/firewall_nonlinux.go

@@ -3,24 +3,12 @@
 
 package routemanager
 
-import "context"
+import (
+	"context"
+	"fmt"
+)
 
-type unimplementedFirewall struct{}
-
-func (unimplementedFirewall) RestoreOrCreateContainers() error {
-	return nil
-}
-func (unimplementedFirewall) InsertRoutingRules(pair routerPair) error {
-	return nil
-}
-func (unimplementedFirewall) RemoveRoutingRules(pair routerPair) error {
-	return nil
-}
-
-func (unimplementedFirewall) CleanRoutingRules() {
-}
-
-// NewFirewall returns an unimplemented Firewall manager
-func NewFirewall(parentCtx context.Context) firewallManager {
-	return unimplementedFirewall{}
+// NewFirewall returns a nil manager
+func NewFirewall(context.Context) (firewallManager, error) {
+	return nil, fmt.Errorf("firewall not supported on this OS")
 }