bugtool: collect IP cache list with numeric identities
bugtool: collect IP cache list with numeric identities

PR #13304 switched `cilium ip list` output to show names for reserved
identities.  In bugtool output we might want the underlying integer
values when debugging, so add the `-n` option. There's still the `cilium
identity list` output to correlate the numeric identities to names.

Address https://github.com/cilium/cilium/pull/13304#issuecomment-700314867

Suggested-by: Joe Stringer <16a9a54ddf4259952e3c118c763138e83693d7fd@cilium.io>
Signed-off-by: Tobias Klauser <9249c549618448e4c699e8032ba6c7f0d7fd4b7f@distanz.ch>

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