[C++][Compute] Sketch a C++ consumer of compute IR

[asfimport]

ARROW-14062 adds a basic compute Intermediate Representation. Allowing c++ compute to consume this and produce ExecPlans will allow more straightforward and less tightly coupled usage of ExecPlans from bindings.

Reporter: Ben Kietzman / @bkietz
Assignee: Ben Kietzman / @bkietz

Subtasks:

• Compute IR source consumer
• Compute IR project consumer
• Compute IR filter consumer
• Compute IR Aggregate consumer
• Expose API for Arrow C++ IR Consumer
• [Python] Expose Arrow C++ Consumer API to pyarrow

PRs and other links:

• GitHub Pull Request #11384

_{Note: This issue was originally created as ARROW-14074. Please see the migration documentation for further details.}

[asfimport]

Ben Kietzman / @bkietz:
Issue resolved by pull request 11384
#11384

[asfimport]

Joris Van den Bossche / @jorisvandenbossche:
Given that we are planning to remove the Compute IR consumer (ARROW-16740, since we now use Substrait instead), I think all those sub-tasks can be closed.
Or is there anything that is still useful / can be repurposed for the Substrait-based consumer APIs? (I suppose those already have its own JIRAs)

cc @westonpace