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/config.rs

@@ -1,4 +1,3 @@
-use crate::fee_recipient_file::FeeRecipientFile;
 use crate::graffiti_file::GraffitiFile;
 use crate::{http_api, http_metrics};
 use clap::ArgMatches;
@@ -44,8 +43,6 @@ pub struct Config {
     pub graffiti_file: Option<GraffitiFile>,
     /// Fallback fallback address.
     pub fee_recipient: Option<Address>,
-    /// Fee recipient file to load per validator suggested-fee-recipients.
-    pub fee_recipient_file: Option<FeeRecipientFile>,
     /// Configuration for the HTTP REST API.
     pub http_api: http_api::Config,
     /// Configuration for the HTTP REST API.
@@ -86,7 +83,6 @@ impl Default for Config {
             graffiti: None,
             graffiti_file: None,
             fee_recipient: None,
-            fee_recipient_file: None,
             http_api: <_>::default(),
             http_metrics: <_>::default(),
             monitoring_api: None,
@@ -206,19 +202,6 @@ impl Config {
             }
         }
 
-        if let Some(fee_recipient_file_path) = cli_args.value_of("suggested-fee-recipient-file") {
-            let mut fee_recipient_file = FeeRecipientFile::new(fee_recipient_file_path.into());
-            fee_recipient_file
-                .read_fee_recipient_file()
-                .map_err(|e| format!("Error reading suggested-fee-recipient file: {:?}", e))?;
-            config.fee_recipient_file = Some(fee_recipient_file);
-            info!(
-                log,
-                "Successfully loaded suggested-fee-recipient file";
-                "path" => fee_recipient_file_path
-            );
-        }
-
         if let Some(input_fee_recipient) =
             parse_optional::<Address>(cli_args, "suggested-fee-recipient")?
         {