Add admission webhooks or something else for arrays in application spec

[korotindev]

soxat@soxat operator-sdk-testing % kubectl create -f deploy/crds/app.korotin.dev_applications_crd.yaml
The CustomResourceDefinition "applications.app.korotin.dev" is invalid:
* spec.validation.openAPIV3Schema.properties[spec].properties[containers].uniqueItems: Forbidden: uniqueItems cannot be set to true since the runtime complexity becomes quadratic
* spec.validation.openAPIV3Schema.properties[spec].properties[containers].items.properties[ports].uniqueItems: Forbidden: uniqueItems cannot be set to true since the runtime complexity becomes quadratic