Create NGINX Agent Docker Container

[mpstefan]

As a maintainer of NGF
I want the NGINX data plane to be instrumented with Agent
So that I can use the management API in Agent to update the data plane from the control plane.

Acceptance

• A container image is created that contains NGINX instrumented with Agent that includes NGF specific modules.

Dev Notes

• Makefile should be updated to use a new dockerfile for this.
• Should be built in the pipeline on the feature branch.
• Saylor's PoC should have some of this already implemented.

Dependencies

• NGINX Agent releases with the features we need to integrate.