feat: let consensus tests configure pipeline, executor, and client

[Rjected]

Allows the consensus tests to configure a real pipeline (with DefaultStages), a real executor, and a real download client. This lets us locally integration test consensus actions, insert blocks that the consensus engine will fetch (for example with the TestFullBlockClient) and perform real block validation in tests.

Fixes #3835

[codecov]

Codecov Report

Merging #3839 (9129198) into main (26b1ffa) will decrease coverage by 0.14%.
The diff coverage is 83.69%.

Impacted Files	Coverage Δ
crates/consensus/beacon/src/engine/mod.rs	75.34% <83.69%> (-1.44%)	⬇️

... and 14 files with indirect coverage changes

Flag	Coverage Δ
integration-tests	15.59% <0.00%> (-0.06%)	⬇️
unit-tests	64.07% <83.69%> (-0.12%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
reth binary	26.49% <ø> (ø)
blockchain tree	83.02% <ø> (ø)
pipeline	87.04% <ø> (ø)
storage (db)	74.32% <ø> (ø)
trie	94.65% <ø> (ø)
txpool	46.82% <ø> (-0.04%)	⬇️
networking	77.55% <ø> (-0.04%)	⬇️
rpc	58.33% <ø> (-0.61%)	⬇️
consensus	64.66% <83.69%> (-0.39%)	⬇️
revm	33.80% <ø> (+0.04%)	⬆️
payload builder	6.61% <ø> (ø)
primitives	88.05% <ø> (-0.02%)	⬇️