Validate that CR name is 'cluster'

[loganmc10]

Fixes #16

This adds a validateCR function which checks that the CR name is cluster. It updates the Ready condition of the CR based on whether this validation succeeded or not.

The validateCR could be expanded in the future to add other validations.

Example of success:

apiVersion: rhsyseng.github.io/v1beta1
kind: ClusterRelocation
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"rhsyseng.github.io/v1beta1","kind":"ClusterRelocation","metadata":{"annotations":{},"name":"cluster"},"spec":{"domain":"hello.com"}}
  creationTimestamp: "2023-05-30T18:10:55Z"
  generation: 1
  name: cluster
  resourceVersion: "423570"
  uid: 4bd05411-e61f-404e-818c-ad6b0e689bf3
spec:
  domain: hello.com
status:
  conditions:
  - lastTransitionTime: "2023-05-30T18:10:57Z"
    message: ""
    observedGeneration: 1
    reason: ValidationSucceeded
    status: "True"
    type: Ready

Example of failure:

apiVersion: rhsyseng.github.io/v1beta1
kind: ClusterRelocation
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"rhsyseng.github.io/v1beta1","kind":"ClusterRelocation","metadata":{"annotations":{},"name":"testname"},"spec":{"domain":"hello.com"}}
  creationTimestamp: "2023-05-30T18:11:16Z"
  generation: 1
  name: testname
  resourceVersion: "423689"
  uid: d2389bf5-f377-4df1-a148-9a6d023b24e8
spec:
  domain: hello.com
status:
  conditions:
  - lastTransitionTime: "2023-05-30T18:11:19Z"
    message: 'invalid name: testname. CR name must be: cluster'
    observedGeneration: 1
    reason: ValidationFailed
    status: "False"
    type: Ready