fix(import): missing versions when importing multi-version crd

[iliapolo]

For some reason, we were assuming a CRD can only contain a single version. We were extracting the first version from the versions property and operating solely on that.

This PR considers all versions in the CRD and appends the version to the FQN to avoid name collisions.
Note that for backwards compatibility, the first version remains un-sufixed.

So, for a CRD with kind MyCrd and versions ['v1alpha1', 'v1beta1'], we will get:

// for the first version - unsufixed
export class MyCrd extends ApiObject { ... };
export interface MyCrdProps { 
  readonly metadata?: ApiObjectMetadata;
  readonly spec?: MyCrdSpec;
};

// for the second version - sufixed
export class MyCrdV1Beta1 extends ApiObject { ... };
export interface MyCrdV1Beta1Props {
  readonly metadata?: ApiObjectMetadata;
  readonly spec?: MyCrdV1Beta1Spec;
}

Where we only used to have:

export class MyCrd extends ApiObject { ... };
export interface MyCrdProps { 
  readonly metadata?: ApiObjectMetadata;
  readonly spec?: MyCrdSpec;
};

Fixes #386

[cdk8s-automation]

💚 All backports created successfully

Status	Branch	Result
✅	1.x

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