e2e disconnected flow with mirror registry (adm and/or mirror plugin)

User Story:

As an Openshift user, I want to be able to use the bootable installer in a disconnected environment with my mirrored image registry:

• Our installer needs to have the ability to configure the image registry location

so that I can

• Install images from this location without contacting the internet.

As an Openshift user, I want to be able to use the bootable installer in a connected environment without a mirrored registry:

• Our installer needs to have a default image registry location

so that I can

• Install images from this location provided by Red Hat.

We are requiring the users to provide a mirrored image registry in a disconnected environment. For connected environment it would be still useful for the user if they want to use a specific registry but we should have a default as well.

Acceptance Criteria:

Description of criteria:

• Upstream documentation
• Bootable installer has a configuration option to provide location of the Image Registry
• Bootable installer has a default value (that works) for the Image Registry
• Point 3

(optional) Out of Scope:

It is out of scope for the Bootable Installer to:

• Mirror the image registry this is up to the user to do first in the disconnected case.
• Add missing images to the users image registry, user is expected to mirror all required images needed in the disconnected case
• The default image registry is to be maintained by other teams at Red Hat.

Engineering Details:

• (optional) https://github/com/link.to.enhancement/
• (optional) https://issues.redhat.com/link.to.spike
• Engineering detail 1
• Engineering detail 2

This requires a design proposal.
This requires/does not require a feature gate.