Clean up solver (#2405)

# Description
There was an external contribution working on a TODO comment inside the
solver crate. This code actually was no longer used anywhere so they
effectively wasted their time.
We also regularly get comments asking about the `solver` crate and
explaining the current state is always a bit weird.

# Changes
I tried to delete everything from the `solver` crate that was not used
in the other crates.

## How to test
CI

crates/driver/src/boundary/mempool.rs

@@ -12,7 +12,6 @@ use {
             submitter::{
                 flashbots_api::FlashbotsApi,
                 public_mempool_api::{PublicMempoolApi, SubmissionNode, SubmissionNodeKind},
-                Strategy,
                 Submitter,
                 SubmitterGasPriceEstimator,
                 SubmitterParams,
@@ -122,14 +121,14 @@ impl Mempool {
                     )],
                     matches!(revert_protection, RevertProtection::Enabled),
                 )),
-                submitted_transactions: pool.add_sub_pool(Strategy::PublicMempool),
+                submitted_transactions: pool.add_sub_pool(),
                 gas_price_estimator: eth.boundary_gas_estimator(),
                 config,
                 eth,
             },
             Kind::MEVBlocker { url, .. } => Self {
                 submit_api: Arc::new(FlashbotsApi::new(reqwest::Client::new(), url.to_owned())?),
-                submitted_transactions: pool.add_sub_pool(Strategy::Flashbots),
+                submitted_transactions: pool.add_sub_pool(),
                 gas_price_estimator: eth.boundary_gas_estimator(),
                 config,
                 eth,

crates/solver/Cargo.toml

@@ -10,10 +10,6 @@ name = "solver"
 path = "src/lib.rs"
 doctest = false
 
-[[bin]]
-name = "solver"
-path = "src/main.rs"
-
 [dependencies]
 anyhow = { workspace = true }
 async-trait = { workspace = true }