Split signature throughput tracking out of FeeCalculator (#8447)

* SDK: Split new `FeeRateGovernor` out of `FeeCalculator`

Leaving `FeeCalculator` to *only* calculate transaction fees

* Replace `FeeCalculator` with `FeeRateGovernor` as appropriate

* Expose recent `FeeRateGovernor` to clients

* Move `burn()` back into `FeeCalculator`

Appease BPF tests

* Revert "Move `burn()` back into `FeeCalculator`"

This reverts commit f3035624307196722b62ff8b74c12cfcc13b1941.

* Adjust BPF `Fee` sysvar test to reflect removal of `burn()` from `FeeCalculator`

* Make `FeeRateGovernor`'s `lamports_per_signature` private

* rebase artifacts

* fmt

* Drop 'Recent'

* Drop _with_commitment variant

* Use a more portable integer for `target_signatures_per_slot`

* Add docs for `getReeRateCalculator` JSON RPC method

* Don't return `lamports_per_signature` in `getFeeRateGovernor` JSONRPC reply

runtime/src/genesis_utils.rs

@@ -1,6 +1,6 @@
 use solana_sdk::{
     account::Account,
-    fee_calculator::FeeCalculator,
+    fee_calculator::FeeRateGovernor,
     genesis_config::GenesisConfig,
     pubkey::Pubkey,
     rent::Rent,
@@ -140,11 +140,11 @@ pub fn create_genesis_config_with_leader_ex(
         solana_stake_program!(),
     ];
 
-    let fee_calculator = FeeCalculator::new(0, 0); // most tests can't handle transaction fees
+    let fee_rate_governor = FeeRateGovernor::new(0, 0); // most tests can't handle transaction fees
     let mut genesis_config = GenesisConfig {
         accounts,
         native_instruction_processors,
-        fee_calculator,
+        fee_rate_governor,
         rent,
         ..GenesisConfig::default()
     };