pinned opm version to non-latest

[operator] updated addons

updated cluster versions

[operator] added printer columns for ClusterVersion and AppliedClusterVersion CRDs

[operator] minor code cleanup

[operator] added status conditions to ClusterAddon (closes #75)

[operator] added status conditions to AppliedClusterVersion (closes #74)
[operator] moved some ClusterVersion defaulting logic to the webhook

reworked README (closes #64)

[operator] added new API for cluster-level application of ClusterVers…

…ion's (closes #63)

[operator] CoreDNS IP is now cached to avoid excessive lookups

[operator] general code cleanup

[metrics-proxy] working pod metrics (closes #58)

[web] added copy button to kubeconfig dialog

[vcluster-sync] enabled synchronisation of OAuthClient resources crea…

…ted in the virtual cluster (closes #57)