Define CheCluster v2alpha1

[metlos]

This is a subtask of #19448.

We need to define the CheCluster version v2alpha1 that is going to be the configuration basis for the che aspects of DevWorkspace.

This version should contain all Devworkspace-related configuration options under spec and should keep all the che7-related configuration (basically the CheCluster v1) under spec.che7.

I image it could take the following form:

apiVersion: v2alpha1
kind: CheCluster
metadata:
  ...
spec:
  che7:
    ... all the options from CheCluster v1
  enabled: false
  che7Enabled: true
  gatewayHost: workspaces.acme.com
  gatewayEnabled: true
  ... related image names and other trivia

The first 3 options (che7, enabled and che7enabled) are there to temporarily to handle the coexistence of che7 server and devworkspace and should probably be removed in the future. The rest of the options is copied from the CheManager which is a temporary CRD used currently by DWCO (https://github.com/che-incubator/devworkspace-che-operator/blob/main/apis/che-controller/v1alpha1/component_types.go#L21).

We need to have the code for this CRD in a place that is consumable by both che-operator and devworkspace-che-operator.

[metlos]

This is superseded by #19845. Once we get to the point where we need to define the new CR version, we can revisit this issue or create a new one.