Provide NetworkPolicy examples for all components

[linkvt]

Depends a bit on #1601 which documents the network flows.

We should provide NetworkPolicy examples that admins can use when deploying the KEDA HTTP Addon in security-hardened environments.
These network policies should include our components and an example application how a user would

Tasks:

• Provide NetworkPolicy examples following the principle of least privilege
• Examples for HTTP Addon component
• Examples for a dummy user application
• Actually verify that it works, e.g. by removing the individual policies to check whether it doesn't afterwards anymore
• Investigate whether we want and can provide these NetworkPolicies in the helm chart

[Akram-saj]

Hi @linkvt I'd like to work on this issue.

[linkvt]

Awesome, thanks! I assigned the issue to you.