feat: consider ingress and egress rules for networkpolicies

[tthvo]

What this PR does / why we need it?

This PR added consideration for discovering second-level unused NetworkPolicies with matching .spec.podSelector, but unmatched pods in Ingress/Egress rules.

See #296 (comment)

kor version: vdev

  _  _____  ____
 | |/ / _ \|  _ \
 | ' / | | | |_) |
 | . \ |_| |  _ <
 |_|\_\___/|_| \_\

Unused resources in namespace: "default"
+---+---------------+---------------------+---------------------------------------------------------+
| # | RESOURCE TYPE |    RESOURCE NAME    |                         REASON                          |
+---+---------------+---------------------+---------------------------------------------------------+
| 1 | NetworkPolicy | test-network-policy | NetworkPolicy Ingress and Egress rules apply to 0 pods |
+---+---------------+---------------------+---------------------------------------------------------+

PR Checklist

• This PR adds K8s exceptions (false positives)
• This PR adds new code
• This PR includes tests for new/existing code
• This PR adds docs

GitHub Issue

Solves #312

Notes for your reviewers

Rules with ipBlock is considered "used" here.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 66.66667% with 24 lines in your changes missing coverage. Please review.

Project coverage is 42.39%. Comparing base (181141d) to head (d60bb53).

Files	Patch %	Lines
pkg/kor/networkpolicies.go	62.50%	11 Missing and 13 partials ⚠️

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #310      +/-   ##
==========================================
+ Coverage   42.01%   42.39%   +0.38%     
==========================================
  Files          61       61              
  Lines        3175     3236      +61     
==========================================
+ Hits         1334     1372      +38     
- Misses       1633     1644      +11     
- Partials      208      220      +12     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[doronkg]

@tthvo I've created a new issue to address this enhancement - #312, please update the description and reference it.
Let us know when the draft is ready to review 💪

[tthvo]

@doronkg @yonahd I think this is ready now for review. I have run some extensive tests but might miss some cases. Please let me know what you think :D