sampler out

[caleb-johnson]

Resolves #363

This is a reference branch where the refactor of the QPD-based circuit cutting workflow will be staged. The primary goal of this PR is to create a lean circuit cutting interface that exposes the Sampler primitive directly to the user.

I will break this into as many smaller PRs as makes sense to facilitate good code review and mitigate any regressions in the docs from so many sudden changes.

[coveralls]

Pull Request Test Coverage Report for Build 5912382665

• 123 of 123 (100.0%) changed or added relevant lines in 2 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.2%) to 91.634%

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Totals
Change from base Build 5911786869:	-0.2%
Covered Lines:	2848
Relevant Lines:	3108

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💛 - Coveralls