Request: Output security identities by default

[joestringer]

Security identities are very helpful in pinpointing whether it's likely that an issue is related to a pod identity, or world identity issues, or even masquerading issues. It would be helpful to print these by default (even if it's just the number) so that when users report issues, we can at least tell a bit more about the likely direction of the flow, whether it's between two pods or a pod and outside, or whether Cilium has assessed the identity of something as belonging "to the world" which has different policy debug paths from pod<->pod identity investigations.

[michi-covalent]

adding more suggestions here (from @pchaigno)

• The FORWARDED/DROPPED at the end is confusing for policy verdicts. Should likely be ALLOWED/DENIED. Maybe FORWARDED could also just be omitted for brevity.
• The context (endpoint ID) in which each event was emitted is not shown in the compact output. That's also often useful to see transitions on pod-to-pod traffic.

we could either:

• update the default compact output format, or
• come up with another output format that's geared towards users who are familiar with cilium internals

[michi-covalent]

ok i'm closing this, it's fixed in #732.

i'll open a separate issue to track how to improve policy verdict events in the compact output.