Initial support for inference extension deployer

[danehans]

Description

Adds initial support for an InferencePool controller and deployer. This controller and deployer are independent of a gateway deployer. For now, both share the GatewayConfig type since refactoring this type would further increase the size of this PR.

API changes

N/A

Code changes

Controller, deployer, and helm pkgs.

CI changes

N/A

Docs changes

Godocs added throughout. User docs will be added in a future PR.

Context

Supports #10411

Interesting decisions

This PR Implements a separate deployer since an InferencePool (and the supporting infra resources) do not depend on a Gateway. Instead, a deployed Gateway will use config from an InferencePool to learn how to connect to it, what failure mode to use, etc.

Testing steps

Unit and integration tests were added. e2e tests are still required and not included here due to the size of the PR.

Notes for reviewers

Refer to the upstream docs for add'l context.

Checklist:

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works

[danehans]

I don't understand why this PR required a bunch of code generation.