feat: add and use a user operation trait

[dancoombs]

Introduce a user operation trait. WIP to test the strategy, needs tons of work to actually get ready to merge, however spec tests pass.

• Implement for v0.6 and v0.7
• Add a variant that can hold either, and also implements the trait
• Make UO specific components generic on the trait:
  • Pool classes
  • Bundle proposer and bundle sender
  • Likely will need some RPC helper functions here too.
• Non-UO specific components use the variant
  • Local/remote client and server classes
  • Makes it easy to communicate between rpc, pool, and builder actors

Related TODOs:

• RPC is hardcoded on v0.6. Introduce new RPC types that can distinguish the required UO type based on the entry point address from ChainSpec. Then create the variant and send to the pool OR use the entry point context (only estimator).
• Local pool runner is hardcoded on v0.6. Needs to take the variant and the ep address, then route to the correct mempool while extracting the correct type.
• Entry point provider, simulation, estimation, need 0.7 specific implementations
• Bundle proposer needs to implement 0.7 specific logic (packing UO before sending).

[codecov]

Codecov Report

Attention: Patch coverage is 48.55617% with 2601 lines in your changes are missing coverage. Please review.

Project coverage is 55.82%. Comparing base (f5d2c6e) to head (73f6d62).

Additional details and impacted files

Files	Coverage Δ
crates/builder/src/server/remote/protos.rs	0.00% <ø> (ø)
crates/pool/src/mempool/mod.rs	100.00% <100.00%> (+10.11%)	⬆️
crates/pool/src/mempool/paymaster.rs	93.62% <100.00%> (+0.02%)	⬆️
crates/pool/src/mempool/reputation.rs	85.25% <ø> (+5.13%)	⬆️
crates/pool/src/server/remote/server.rs	0.00% <ø> (ø)
crates/provider/src/ethers/provider.rs	0.00% <ø> (ø)
crates/provider/src/traits/provider.rs	100.00% <ø> (ø)
crates/rpc/src/admin.rs	0.00% <ø> (ø)
crates/rpc/src/eth/events/mod.rs	100.00% <100.00%> (ø)
crates/rpc/src/eth/mod.rs	0.00% <ø> (ø)
... and 64 more

... and 1 file with indirect coverage changes

Flag	Coverage Δ
unit-tests	55.82% <48.55%> (-2.13%)	⬇️

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

Components	Coverage Δ
rundler binary	0.00% <0.00%> (ø)
builder	50.64% <43.94%> (-1.15%)	⬇️
dev	0.00% <0.00%> (ø)
pool	65.33% <66.16%> (+0.85%)	⬆️
provider	9.08% <11.94%> (+8.66%)	⬆️
rpc	29.08% <36.86%> (-5.27%)	⬇️
sim	84.33% <58.23%> (-2.24%)	⬇️
tasks	∅ <ø> (∅)
types	66.50% <63.60%> (-20.80%)	⬇️
utils	16.73% <ø> (ø)

[0xfourzerofour]

Pretty wild PR good job on it. I wouldn't really change much just a couple nit things and questions