feat[common]: Add tests and refactor for networkpolicies

[PrivatePuffin]

Is your feature request related to a problem?

Currently networkPolicies are not actively tested nor supported, hence they dont comply to our coding standards.

Describe the solution you'd like

We should ensure they are (unit)tested and comply to all our standards

Describe alternatives you've considered

.

Additional context

NetworkPolicies are a vital component of kubernetes security, its absolutely crucial we support them before we can consider TrueCharts Common "production-use" ready.

I've read and agree with the following

• [x] I've checked all open and closed issues and my request is not there.
• [x] I've checked all open and closed pull requests and my request is not there.