feat: add remote cluster apply

[Skarlso]

Closes #101

Adds the ability to apply CRDs into a remote cluster.

Testing:

kind create cluster --name one
kind create cluster --name external
kind get kubeconfig --internal --name external>kubeconfig.yaml
kind get kubeconfig --name external>kubeconfig-external.yaml
kubectl create secret generic kubeconfig --from-file=kubeconfig=kubeconfig.yaml
kubectl config use-context kind-one

...
tilt up

Created some secrets using the kubeconfig and used the following CRD:

apiVersion: delivery.crd-bootstrap/v1alpha1
kind: Bootstrap
metadata:
  name: bootstrap-sample
spec:
  interval: 10s
  source:
    url:
      url: https://raw.githubusercontent.com/krok-o/operator/main/config/crd/bases/delivery.krok.app_krokevents.yaml
  kubeConfig:
    secretRef:
      secretRef:
        name: kubeconfig
        key: kubeconfig

After that, verified that the remote cluster had the CRD:

k get customresourcedefinitions --kubeconfig kubeconfig-external.yaml
NAME                           CREATED AT
krokevents.delivery.krok.app   2024-08-07T06:37:47Z