Flatten the repository structure

[0xFelix]

Is your feature request related to a problem? Please describe:

The repository is making extensive use of kustomize, which at some places makes it harder than necessary to understand how everything comes together.

Describe the solution you'd like:

We should try to flatten the repo structure and avoid unnecessary deeply nested directory structures and workarounds to Kustomize's behavior where possible.

E.g. it would be nice to flatten instancetypes from this

instancetypes/cx:
1 VirtualMachineClusterInstancetype VirtualMachineInstancetype kustomization.yaml

to this:

instancetypes/cx1:
cx1.yaml sizes.yaml kustomization.yaml

Describe alternatives you've considered:
A clear and concise description of any alternative solutions or features you've considered.

Additional context:
Add any other context or screenshots about the feature request here.

[fabiand]

❤️

[kubevirt-bot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
Stale issues rot after an additional 30d of inactivity and eventually close.

If this issue is safe to close now please do so with /close.

/lifecycle stale

[fabiand]

/remove-lifecycle stale

[kubevirt-bot]

Issues go stale after 90d of inactivity.
Mark the issue as fresh with /remove-lifecycle stale.
Stale issues rot after an additional 30d of inactivity and eventually close.

If this issue is safe to close now please do so with /close.

/lifecycle stale

[lyarwood]

/remove-lifecycle stale