Create CRD for WAFPolicy

[ciarams87]

As a user of NGF with an NGINX One subscription
I want a method to configure WAF protection on my Gateways and Routes
So that I can enable the NAP WAF feature for the applications that need it.

Acceptance:

• A CRD for WAFPolicy is defined according to the enhancement proposal under "WafPolicy Custom Resource with Policy Attachment"
• The name for "WAFPolicy" follows Kubernetes naming conventions.