Rpc: introduce get_inflation_reward rpc call (#16278)

* feat: introduce get_inflation_reward rpc call

* fix: style suggestions

* fix: more style changes and match how other rpc functions are defined

* feat: get reward for a single epoch

* feat: default to the most recent epoch

* fix: don't factor out get_confirmed_block

* style: introduce from impl for RpcEncodingConfigWrapper

* style: bring commitment into variable

* feat: support multiple pubkeys for get_inflation_reward

* feat: add get_inflation_reward to rpc client

* feat: return rewards in order

* fix: rename pubkeys to addresses

* docs: introduce jsonrpc docs for get_inflation_reward

* style: early return in map (not sure which is more idiomatic)

* fix: call the rpc client function args addresses as well

* fix: style

* fix: filter out only addresses we care about

* style: make this more idiomatic

* fix: change rpc client epoch to optional and include some docs edits

* feat: filter out rent rewards in get_inflation_reward

* feat: add option epoch config param to get_inflation_reward

* feat: rpc client get_inflation_reward takes epoch instead of config and some filter staking and voting rewards

client/src/rpc_response.rs

@@ -362,6 +362,15 @@ pub struct RpcPerfSample {
     pub sample_period_secs: u16,
 }
 
+#[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct RpcInflationReward {
+    pub epoch: Epoch,
+    pub effective_slot: Slot,
+    pub amount: u64,       // lamports
+    pub post_balance: u64, // lamports
+}
+
 impl From<ConfirmedTransactionStatusWithSignature> for RpcConfirmedTransactionStatusWithSignature {
     fn from(value: ConfirmedTransactionStatusWithSignature) -> Self {
         let ConfirmedTransactionStatusWithSignature {