This turns admitomatic into a self-standing service that can be used as
an admission controller.
I've tested this E2E on a local k3s server, and have some early test
code for that - but that'll land up in a follow up CR, as it first needs
to be cleaned up.
Change-Id: I46da0fc49f9d1a3a1a96700a36deb82e5057249b
This is the beginning of a validating admission controller which we will
use to permit end-users access to manage Ingresses.
This first pass implements an ingressFilter, which is the main structure
through which allowed namespace/dns combinations will be allowed. The
interface is currently via a test, but in the future this will likely be
configured via a command line, or via a serialized protobuf config.
Change-Id: I22dbed633ea8d8e1fa02c2a1598f37f02ea1b309