Add new rules to update DNAT rules for Kubernetes operator's
HA ingress where it's expected that rules will be added/removed
frequently (so we don't want to keep old rules around or rewrite
existing rules unnecessarily):
- allow deleting DNAT rules using metadata lookup
- allow inserting DNAT rules if they don't already
exist (using metadata lookup)
Updates tailscale/tailscale#15895
Signed-off-by: Irbe Krumina <irbe@tailscale.com>
Co-authored-by: chaosinthecrd <tom@tmlabs.co.uk>