User Story:

• As an openshift-install user I want to be able to continue to use aws.subnets during deprecation (a warning will show)
• As an openshift developer, I only want a single code path for subnets (via upconversion)

Acceptance Criteria:

Description of criteria:

• Validation that both fields are not simultaneously specified
• When aws.subnets is specified, it's upconverted into aws.vpc.subnets
• Existing pkg/types/aws/Subnets type is renamed to DeprecatedSubnets
• Remove all (or as many possible) usages of DeprecatedSubnets, replaced with the new vpc.Subnets field
  • We may need to keep usage of DeprecatedSubnets for certain validations
• Warning when using deprecated field

(optional) Out of Scope:

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Engineering Details:

• Conversion package: https://github.com/openshift/installer/tree/main/pkg/types/conversion
• Review how subnets are used in https://github.com/openshift/installer/blob/main/pkg/asset/installconfig/aws/metadata.go and whether any changes/refactoring is needed