Use upstream version of capd controller with RKE2

What does this MR do and why?

THis update is the result of sylva-projects/sylva-elements/helm-charts/sylva-capi-cluster!313 (merged). Removed the rke customization for capd. Added a deployment test job for rke2-capd. Added a short intro for capd.

Related reference(s)

sylva-projects/sylva-elements/helm-charts/sylva-capi-cluster!313 (merged)

Test coverage

Added a deployment test job for rke2-capd.

Closes #950 (closed)