KnativeEventing: Allow to set HostNetwork via spec.*.hostNetwork

[kahirokunn]

Problem
After building a vxlan with EKS, I cannot connect to the webhook pod from controlplane in EKS and I get an Address is not allowed error.
To solve this problem, I need to set hostNetwork: true and dnsPolicy: ClusterFirstWithHostNet.
Therefore, we need an option that can override hostNetwork.
If hostNetwork is true, dnsPolicy is recommended to set ClusterFirstWithHostNet, so it would be kind to set it automatically.

Persona:
Which persona is this feature for?

Exit Criteria
A measurable (binary) test that would indicate that the problem has been resolved.

Time Estimate (optional):
How many developer-days do you think this may take to resolve?

Additional context (optional)
Add any other context about the feature request here.

[github-actions]

This issue is stale because it has been open for 90 days with no
activity. It will automatically close after 30 more days of
inactivity. Reopen the issue with /reopen. Mark the issue as
fresh by adding the comment /remove-lifecycle stale.

[kahirokunn]

Keep

[github-actions]

This issue is stale because it has been open for 90 days with no
activity. It will automatically close after 30 more days of
inactivity. Reopen the issue with /reopen. Mark the issue as
fresh by adding the comment /remove-lifecycle stale.

[kahirokunn]

keep

[github-actions]

This issue is stale because it has been open for 90 days with no
activity. It will automatically close after 30 more days of
inactivity. Reopen the issue with /reopen. Mark the issue as
fresh by adding the comment /remove-lifecycle stale.

[kahirokunn]

Keep