🌱 Split v1alpha6 & v1alpha7 conversion into multiple files

[mdbooth]

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.

Note that this is currently based on top of #1920. We could merge it separately fairly easily. The only conflict there is the addition of the Convertible interface on OpenStackClusterTemplateList. However, I'm hoping the webhooks change can merge quickly.

• [x] Land https://github.com/kubernetes-sigs/cluster-api-provider-openstack/pull/1920 and rebase

/hold

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: mdbooth

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/kubernetes-sigs/cluster-api-provider-openstack/blob/main/OWNERS)~~ [mdbooth] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[netlify[bot]]

✅ Deploy Preview for kubernetes-sigs-cluster-api-openstack ready!

Name	Link
🔨 Latest commit	1eca0903b4b47f7852b0982430ae9d4ec670ce40
🔍 Latest deploy log	https://app.netlify.com/sites/kubernetes-sigs-cluster-api-openstack/deploys/65e71761aab5860008d8090c
😎 Deploy Preview	https://deploy-preview-1923--kubernetes-sigs-cluster-api-openstack.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[mdbooth]

/hold cancel

[mdbooth]

/lgtm

Thank you! This was going to be a massive merge conflict magnet 😬