Implement feerecipient API for keymanager (#3213)

## Issue Addressed

* #3173 

## Proposed Changes

Moved all `fee_recipient_file` related logic inside the `ValidatorStore` as it makes more sense to have this all together there. I tested this with the validators I have on `mainnet-shadow-fork-5` and everything appeared to work well. Only technicality is that I can't get the method to return `401` when the authorization header is not specified (it returns `400` instead). Fixing this is probably quite difficult given that none of `warp`'s rejections have code `401`.. I don't really think this matters too much though as long as it fails.

validator_client/src/preparation_service.rs

@@ -1,8 +1,5 @@
 use crate::beacon_node_fallback::{BeaconNodeFallback, RequireSynced};
-use crate::{
-    fee_recipient_file::FeeRecipientFile,
-    validator_store::{DoppelgangerStatus, ValidatorStore},
-};
+use crate::validator_store::{DoppelgangerStatus, ValidatorStore};
 use bls::PublicKeyBytes;
 use environment::RuntimeContext;
 use parking_lot::RwLock;
@@ -31,8 +28,6 @@ pub struct PreparationServiceBuilder<T: SlotClock + 'static, E: EthSpec> {
     slot_clock: Option<T>,
     beacon_nodes: Option<Arc<BeaconNodeFallback<T, E>>>,
     context: Option<RuntimeContext<E>>,
-    fee_recipient: Option<Address>,
-    fee_recipient_file: Option<FeeRecipientFile>,
 }
 
 impl<T: SlotClock + 'static, E: EthSpec> PreparationServiceBuilder<T, E> {
@@ -42,8 +37,6 @@ impl<T: SlotClock + 'static, E: EthSpec> PreparationServiceBuilder<T, E> {
             slot_clock: None,
             beacon_nodes: None,
             context: None,
-            fee_recipient: None,
-            fee_recipient_file: None,
         }
     }
 
@@ -67,16 +60,6 @@ impl<T: SlotClock + 'static, E: EthSpec> PreparationServiceBuilder<T, E> {
         self
     }
 
-    pub fn fee_recipient(mut self, fee_recipient: Option<Address>) -> Self {
-        self.fee_recipient = fee_recipient;
-        self
-    }
-
-    pub fn fee_recipient_file(mut self, fee_recipient_file: Option<FeeRecipientFile>) -> Self {
-        self.fee_recipient_file = fee_recipient_file;
-        self
-    }
-
     pub fn build(self) -> Result<PreparationService<T, E>, String> {
         Ok(PreparationService {
             inner: Arc::new(Inner {
@@ -92,8 +75,6 @@ impl<T: SlotClock + 'static, E: EthSpec> PreparationServiceBuilder<T, E> {
                 context: self
                     .context
                     .ok_or("Cannot build PreparationService without runtime_context")?,
-                fee_recipient: self.fee_recipient,
-                fee_recipient_file: self.fee_recipient_file,
                 validator_registration_cache: RwLock::new(HashMap::new()),
             }),
         })
@@ -106,8 +87,6 @@ pub struct Inner<T, E: EthSpec> {
     slot_clock: T,
     beacon_nodes: Arc<BeaconNodeFallback<T, E>>,
     context: RuntimeContext<E>,
-    fee_recipient: Option<Address>,
-    fee_recipient_file: Option<FeeRecipientFile>,
     // Used to track unpublished validator registration changes.
     validator_registration_cache:
         RwLock<HashMap<ValidatorRegistrationKey, SignedValidatorRegistrationData>>,
@@ -301,23 +280,6 @@ impl<T: SlotClock + 'static, E: EthSpec> PreparationService<T, E> {
     {
         let log = self.context.log();
 
-        let fee_recipient_file = self
-            .fee_recipient_file
-            .clone()
-            .map(|mut fee_recipient_file| {
-                fee_recipient_file
-                    .read_fee_recipient_file()
-                    .map_err(|e| {
-                        error!(
-                            log,
-                            "Error loading fee-recipient file";
-                            "error" => ?e
-                        );
-                    })
-                    .unwrap_or(());
-                fee_recipient_file
-            });
-
         let all_pubkeys: Vec<_> = self
             .validator_store
             .voting_pubkeys(DoppelgangerStatus::ignored);
@@ -327,22 +289,7 @@ impl<T: SlotClock + 'static, E: EthSpec> PreparationService<T, E> {
             .filter_map(|pubkey| {
                 // Ignore fee recipients for keys without indices, they are inactive.
                 let validator_index = self.validator_store.validator_index(&pubkey)?;
-
-                // If there is a `suggested_fee_recipient` in the validator definitions yaml
-                // file, use that value.
-                let fee_recipient = self
-                    .validator_store
-                    .suggested_fee_recipient(&pubkey)
-                    .or_else(|| {
-                        // If there's nothing in the validator defs file, check the fee
-                        // recipient file.
-                        fee_recipient_file
-                            .as_ref()?
-                            .get_fee_recipient(&pubkey)
-                            .ok()?
-                    })
-                    // If there's nothing in the file, try the process-level default value.
-                    .or(self.fee_recipient);
+                let fee_recipient = self.validator_store.get_fee_recipient(&pubkey);
 
                 if let Some(fee_recipient) = fee_recipient {
                     Some(map_fn(pubkey, validator_index, fee_recipient))