Add support for NGINX Agent 3 to support NGINX One

[brianehlert]

Agent 2 was added to NIC + WAF container builds to support the Security Monitor experience with NGINX Instance Manager for violation management.

In November 2023, NGINX announced NGINX One. A new centralized management experience that will bring together all of your NGINX real estate into a single, unified view of the infrastructure and applications.

The Agent component is evolving to better serve a number of use cases, one of which is NGINX Ingress Controller. To align with the NGINX One evolution, NIC shall include Agent as a component to all builds.

The configuration experience shall be through the GlobalConfiguration resource with an experience that encompasses a similar experience to the following:

• if agent is not configured, it shall not run in the background
• the certificates use to secure agent communication with NIM/SaaS console shall be Kubernetes secrets and thus handled and treated like any other secret.
• customers shall be able to set their tenant or NIM instance FQDN
• SaaS console customers need to additionally provide a tenant ID
• customers shall have an option to support self-signed certificates (not enforcing certificate validation)

The agent configuration experience shall be simplified to the point that customers provide a minimal amount of information to configure agent connectivity to NIM/SaaS.
The Agent 2 method of requiring customers manage a configmap blob and volume, while it does work, it is overly complex and complicated. It exposes too much complexity that is unnecessary and potentially at odds with the overall NIC value proposition.