Split v1alpha6&v1alpha7 conversion into multiple files

This is 100% code motion with no code changes whatsoever.

conversion.go has become unwieldy, making changes to it harder to
understand. This simply splits it into several files based on the
corresponding _types.go.

We don't touch v1alpha5 as it's about to be deleted. It can stay a mess.

api/v1alpha6/openstackclustertemplate_conversion.go

@@ -0,0 +1,115 @@
+/*
+Copyright 2023 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+	http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package v1alpha6
+
+import (
+	ctrlconversion "sigs.k8s.io/controller-runtime/pkg/conversion"
+
+	infrav1 "sigs.k8s.io/cluster-api-provider-openstack/api/v1beta1"
+	"sigs.k8s.io/cluster-api-provider-openstack/pkg/utils/conversion"
+)
+
+var _ ctrlconversion.Convertible = &OpenStackClusterTemplate{}
+
+func (r *OpenStackClusterTemplate) ConvertTo(dstRaw ctrlconversion.Hub) error {
+	dst := dstRaw.(*infrav1.OpenStackClusterTemplate)
+
+	return conversion.ConvertAndRestore(
+		r, dst,
+		Convert_v1alpha6_OpenStackClusterTemplate_To_v1beta1_OpenStackClusterTemplate, Convert_v1beta1_OpenStackClusterTemplate_To_v1alpha6_OpenStackClusterTemplate,
+		v1alpha6OpenStackClusterTemplateRestorer, v1beta1OpenStackClusterTemplateRestorer,
+	)
+}
+
+func (r *OpenStackClusterTemplate) ConvertFrom(srcRaw ctrlconversion.Hub) error {
+	src := srcRaw.(*infrav1.OpenStackClusterTemplate)
+
+	return conversion.ConvertAndRestore(
+		src, r,
+		Convert_v1beta1_OpenStackClusterTemplate_To_v1alpha6_OpenStackClusterTemplate, Convert_v1alpha6_OpenStackClusterTemplate_To_v1beta1_OpenStackClusterTemplate,
+		v1beta1OpenStackClusterTemplateRestorer, v1alpha6OpenStackClusterTemplateRestorer,
+	)
+}
+
+var _ ctrlconversion.Convertible = &OpenStackClusterTemplateList{}
+
+func (r *OpenStackClusterTemplateList) ConvertTo(dstRaw ctrlconversion.Hub) error {
+	dst := dstRaw.(*infrav1.OpenStackClusterTemplateList)
+	return Convert_v1alpha6_OpenStackClusterTemplateList_To_v1beta1_OpenStackClusterTemplateList(r, dst, nil)
+}
+
+func (r *OpenStackClusterTemplateList) ConvertFrom(srcRaw ctrlconversion.Hub) error {
+	src := srcRaw.(*infrav1.OpenStackClusterTemplateList)
+	return Convert_v1beta1_OpenStackClusterTemplateList_To_v1alpha6_OpenStackClusterTemplateList(src, r, nil)
+}
+
+/* Restorers */
+
+var v1alpha6OpenStackClusterTemplateRestorer = conversion.RestorerFor[*OpenStackClusterTemplate]{
+	"spec": conversion.HashedFieldRestorer(
+		func(c *OpenStackClusterTemplate) *OpenStackClusterSpec {
+			return &c.Spec.Template.Spec
+		},
+		restorev1alpha6ClusterSpec,
+	),
+}
+
+var v1beta1OpenStackClusterTemplateRestorer = conversion.RestorerFor[*infrav1.OpenStackClusterTemplate]{
+	"externalNetwork": conversion.UnconditionalFieldRestorer(
+		func(c *infrav1.OpenStackClusterTemplate) *infrav1.NetworkFilter {
+			return &c.Spec.Template.Spec.ExternalNetwork
+		},
+	),
+	"disableExternalNetwork": conversion.UnconditionalFieldRestorer(
+		func(c *infrav1.OpenStackClusterTemplate) *bool {
+			return &c.Spec.Template.Spec.DisableExternalNetwork
+		},
+	),
+	"router": conversion.UnconditionalFieldRestorer(
+		func(c *infrav1.OpenStackClusterTemplate) **infrav1.RouterFilter {
+			return &c.Spec.Template.Spec.Router
+		},
+	),
+	"networkMtu": conversion.UnconditionalFieldRestorer(
+		func(c *infrav1.OpenStackClusterTemplate) *int {
+			return &c.Spec.Template.Spec.NetworkMTU
+		},
+	),
+	"bastion": conversion.HashedFieldRestorer(
+		func(c *infrav1.OpenStackClusterTemplate) **infrav1.Bastion {
+			return &c.Spec.Template.Spec.Bastion
+		},
+		restorev1beta1Bastion,
+	),
+	"subnets": conversion.HashedFieldRestorer(
+		func(c *infrav1.OpenStackClusterTemplate) *[]infrav1.SubnetFilter {
+			return &c.Spec.Template.Spec.Subnets
+		},
+		restorev1beta1Subnets,
+	),
+	"allNodesSecurityGroupRules": conversion.HashedFieldRestorer(
+		func(c *infrav1.OpenStackClusterTemplate) *infrav1.ManagedSecurityGroups {
+			return c.Spec.Template.Spec.ManagedSecurityGroups
+		},
+		restorev1beta1ManagedSecurityGroups,
+	),
+	"managedSubnets": conversion.UnconditionalFieldRestorer(
+		func(c *infrav1.OpenStackClusterTemplate) *[]infrav1.SubnetSpec {
+			return &c.Spec.Template.Spec.ManagedSubnets
+		},
+	),
+}