add a new CRD to delegate vpc resource requests

[haouc]

Issue #, if available:

Description of changes:
We want to add a new CRD to delegate communications between this controller and VPC CNI, or other operators from dataplane in the future.

Design considerations

* The CRD object will be one-to-one mapping to worker node
    * one static object per node and last through the node lifespan
    * the object maps to VPC resources and EKS managed featured on the mapped node
* Instead of using v1beta1 we use v1alpha1 for easier, more compatible and conventional development iterations
* Adding Spec and Status
    * Spec: providing a description of the characteristics we want this CRD to have
        * Enabled features are listed as feature flags
            * SecurityGroupForPods
            * CustomNetworking
            * ...
    * Status: (Currently is empty) describing the current state of the VPC resources managed through this CRD, supplied and updated by the EKS networking addons.
        * Future potential use cases for VPC resources, for instance, various types of ENIs
            * list of trunk interfaces
            * list of primary interface
            * list of secondary interfaces
            * list of security groups
            * list of IP addresses to support warm target for branch interfaces
* Using name CNINode/CNINodes which are aligned with Kubernetes well adopted API extensions, such as CSI, CRI, and etc.
* Using enum for Spec and Status
* Using feature flag similar concept for Spec items
* metadata ObjectReference will be provided during creation to handle cascade deletion open node deletion events
* Will add Finalizer to control the GC process (design in process)
    * The Finalizer will refer to resources listed in Status 
* VPC RC will be responsible to CREATE/PATCH/DELET the CRD objects

Tests:

Created an object of the CRD

% k get cnd
NAME              FEATURES
cninode-example   ["SecurityGroupsForPods","CustomNetworking"]

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[jdn5126]

Definition looks good to me. I'll give others a chance to review before approving

[ellistarn]

Nice! A couple of minor optional comments.

[ellistarn]

Nice! A couple of minor optional comments.

[ellistarn]

Nice! A couple of minor optional comments.