Use consistent stage1, stage1to2, stage2, etc names

[stephen-soltesz]

This change updates stage names to use a consistent nomenclature.

Previously, stage1 images requested a stage2.ipxe target, and this was confusing me since stage1 was reading and running scripts named "stage2". Instead, now stage1 images request stage1 targets, stage2
images request stage2 tagets, etc.

By example, a boot sequence will look like:

• stage1 image requests stage1.ipxe from epoxy server
• epoxy server returns the URL to a stage1to2.ipxe script
• stage1 runs the stage1to2 script and boots stage2
• stage2 image requests stage2.json from epoxy server
• epoxy server returns the URL to a stage2to3.json config
• stage2 runs the stage2to3 config and boots stage3.
• ... etc.

The following simple rule should apply now: "a client stage requests the corresponding stage name from the server".

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This change is 

[yachang]

Looks good overall. Only one confusing part: Since you have "stage1to2", do you have "stage2to3"?

If there is no "stage2", how about just name it "stage2" and you already have documentation like:

"... is the absolute URL to an iPXE script for booting stage1 to stage2."

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Review status: 0 of 9 files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[stephen-soltesz]

Yes, there will be a stage2to3 reference as well. The current code base doesn't have that yet b/c I haven't written it yet! :D

I can't use just "stage2" because there will also be a stage2 target that needs a separate name.

This change is just to rename things to use what I think is a simpler naming convention so that I can add these additional pieces. e.g. stage1 images request stage1 targets, stage2 images request stage2 targets, and the stage1to2 or stage2to3 are user-provided configs that manage the transition from stage1 to stage2 (or stage2 to stage3).

Does that help?

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Review status: 0 of 9 files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[yachang]

Thanks for the explanation!

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Review status: 0 of 9 files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable

[yachang]

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Review status: 0 of 9 files reviewed at latest revision, all discussions resolved.

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Comments from Reviewable