README: Remove obsolete badges
README: Remove obsolete badges

* We are no longer using docker registry so the number of pulls has become stale.
* The referenced build pipeline is no longer maintained. The GitHub
  actions will be the place to look for build health.

Signed-off-by: Thomas Graf <5f50a84c1fa3bcff146405017f36aec1a10a9e38@cilium.io>

tgraf/cilium,cilium/cilium,michi-covalent/cilium,cilium/cilium,cilium/cilium,tgraf/cilium,michi-covalent/cilium,michi-covalent/cilium,tklauser/cilium,michi-covalent/cilium,michi-covalent/cilium,tgraf/cilium,tgraf/cilium,tklauser/cilium,tklauser/cilium,cilium/cilium,tgraf/cilium,tklauser/cilium,tgraf/cilium,tklauser/cilium,cilium/cilium