[C++][Acero] Refactor and fix backpressure in all ExecNodes

[gitmodimo]

Describe the enhancement requested

The focus of this issue is first to unify and fix Acero ExecNodes and then to simplify implementation of specific exec nodes by factoring out few infrastructural concepts. This is a followup to discussion #47331.

I will update this issue with current progress.

Unification and infrastructure tasks:

• [C++][Acero] Isolate BackpressureHandler #47384 - Ready to merge
• [C++][Acero] Create BackpressureSource and BackpressureCombiner #47385 - Ready to merge
• [C++][Acero] Introduce Backpressure in PushGenerator #47387 - Depends on #47384
• [C++][Acero] Add pipe_sink, pipe_source and pipe_tee nodes to enable more complex execution plans and query batching. #45434 - Depends on #47385
• Add Acero stream guarantees

Backpressure and ordering tasks:

• Fix ordering and backpressure in SortedMerge
• Fix ordering and backpressure in aggregate nodes - Depends on #47385
• [C++][Acero] Asofjoin does not propagate pause upstream #46421 - Ready to merge
• [C++][Dataset] Preserve order when writing dataset using TeeNode #46454 - Ready to merge

Refactor tasks:

• Add ExecNodeAdapter that handles different access patterns

Component(s)

C++