Refactor incremental spmd algos

[ethanglaser]

Description

Add a comprehensive description of proposed changes

List associated issue number(s) if exist(s): #6 (for example)

Documentation PR (if needed): #1340 (for example)

Benchmarks PR (if needed): IntelPython/scikit-learn_bench#155 (for example)

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[ethanglaser]

/intelci: run

[ethanglaser]

/intelci: run

[codecov]

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[icfaust]

I know this is still a WIP, but maybe we should have a chat about strategy?

[icfaust]

I think this was done for the wonkiness of the get_backend + when the spmd policy is used and when the dpc policy is used.

[icfaust]

Zero copy support will move away from support input format, as we will fully generate #2206 #2207 and #2189