feat: parse openvswitch for any netplan interface

The openvswitch stanza can apply to any interface, so we remove it from
the specific bridge and VLAN devices, and add it to the generic
interface type that those embed.

network/netplan/netplan.go

@@ -52,6 +52,16 @@ type Interface struct {
 	// specified, this instructs netplan not to bring any ipv4/ipv6 address
 	// up.
 	LinkLocal *[]string `yaml:"link-local,omitempty"`
+
+	// According to the netplan examples, this section typically includes
+	// some OVS-specific configuration bits. However, MAAS may just
+	// include an empty block to indicate the presence of an OVS-managed
+	// bridge (LP1942328). As a workaround, we make this an optional map
+	// so we can tell whether it is present (but empty) vs not being
+	// present.
+	//
+	// See: https://github.com/canonical/netplan/blob/main/examples/openvswitch.yaml
+	OVSParameters *map[string]interface{} `yaml:"openvswitch,omitempty"`
 }
 
 // Ethernet defines fields for just Ethernet devices
@@ -61,11 +71,13 @@ type Ethernet struct {
 	SetName   string            `yaml:"set-name,omitempty"`
 	Interface `yaml:",inline"`
 }
+
 type AccessPoint struct {
 	Password string `yaml:"password,omitempty"`
 	Mode     string `yaml:"mode,omitempty"`
 	Channel  int    `yaml:"channel,omitempty"`
 }
+
 type Wifi struct {
 	Match        map[string]string      `yaml:"match,omitempty"`
 	SetName      string                 `yaml:"set-name,omitempty"`
@@ -89,16 +101,6 @@ type Bridge struct {
 	Interfaces []string `yaml:"interfaces,omitempty,flow"`
 	Interface  `yaml:",inline"`
 	Parameters BridgeParameters `yaml:"parameters,omitempty"`
-
-	// According to the netplan examples, this section typically includes
-	// some OVS-specific configuration bits. However, MAAS may just
-	// include an empty block to indicate the presence of an OVS-managed
-	// bridge (LP1942328). As a workaround, we make this an optional map
-	// so we can tell whether it is present (but empty) vs not being
-	// present.
-	//
-	// See: https://github.com/canonical/netplan/blob/main/examples/openvswitch.yaml
-	OVSParameters *map[string]interface{} `yaml:"openvswitch,omitempty"`
 }
 
 type Route struct {
@@ -142,10 +144,9 @@ type Netplan struct {
 
 // VLAN represents the structures for defining VLAN sections
 type VLAN struct {
-	Id            *int   `yaml:"id,omitempty"`
-	Link          string `yaml:"link,omitempty"`
-	Interface     `yaml:",inline"`
-	OVSParameters *map[string]interface{} `yaml:"openvswitch,omitempty"`
+	Id        *int   `yaml:"id,omitempty"`
+	Link      string `yaml:"link,omitempty"`
+	Interface `yaml:",inline"`
 }
 
 // Bond is the interface definition of the bonds: section of netplan