[ENHANCEMENT] Add Northbound traffic support for ANP API

[tssurya]

Is your enhancement request related to a problem? Please describe.
This is follow of up of #28
This issue tracks adding support for northbound traffic use case and also host-networked pod traffic use case for ANP from CNI pods.

Describe the solution you'd like
#117 outlines the details, it has undergone some rounds of review already at #86

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

### Tasks
- [ ] https://github.com/kubernetes-sigs/network-policy-api/pull/117
- [ ] https://github.com/kubernetes-sigs/network-policy-api/pull/143
- [ ] Document egress samples
- [ ] https://github.com/kubernetes-sigs/network-policy-api/pull/144
- [ ] https://github.com/kubernetes-sigs/network-policy-api/pull/185
- [ ] https://github.com/kubernetes-sigs/network-policy-api/pull/193

[tssurya]

/assign @tssurya

[tssurya]

Now that the Provisional NPEP is done, I am working on PoC to implement it and then will re-open the NPEP in the implementable phase with link to PoC.