Restructured to be closer to HTML partials version.

[alankent]

This PR is not intended to be merged.

This still has lots of data-amp-bind-* in it, without loading up AmpBind. But it shows progress of renaming all the components to align with the HTML partials version.

It also moves all the AMP State variables from global state to a single nested group. This is not the final version - it should have multiple global namespaces (not one per variable, not one for everything).

@sebastianbenz

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