[Do Not Merge] POS MVSU experiment

[joshheald]

Description

This is an experiment moving the ItemList to an MVSU approach.

If you go through the commits, you can see a reverted commit which experiments with making the itemlist state wholly the responsibility of the ItemListView, which would be great but doesn't work because of the way we handle the empty/error/initialLoading states on the parent DashboardView.

I don't think that's insurmountable, but didn't want to burn too much time on it for a POC.

[dangermattic]

	2 Warnings
⚠️	View files have been modified, but no screenshot or video is included in the pull request. Consider adding some for clarity.
⚠️	This PR is larger than 300 lines of changes. Please consider splitting it into smaller PRs for easier and faster reviews.

	1 Message
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📲 You can test the changes from this Pull Request in WooCommerce iOS by scanning the QR code below to install the corresponding build.

	App Name	WooCommerce iOS
	Build Number	pr14291-2013bd9
	Version	20.9
	Bundle ID	com.automattic.alpha.woocommerce
	Commit	2013bd9
	App Center Build	WooCommerce - Prototype Builds #11418

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