Integrate tracing (#6339)

Tracing Integration
- [reference](5bbf1859e9/projects/project-ideas.md (L297))


  - [x] replace slog & log with tracing throughout the codebase
- [x] implement custom crit log
- [x] make relevant changes in the formatter
- [x] replace sloggers
- [x] re-write SSE logging components

cc: @macladson @eserilev

beacon_node/client/src/compute_light_client_updates.rs

@@ -2,8 +2,8 @@ use beacon_chain::{BeaconChain, BeaconChainTypes, LightClientProducerEvent};
 use beacon_processor::work_reprocessing_queue::ReprocessQueueMessage;
 use futures::channel::mpsc::Receiver;
 use futures::StreamExt;
-use slog::{error, Logger};
 use tokio::sync::mpsc::Sender;
+use tracing::error;
 
 // Each `LightClientProducerEvent` is ~200 bytes. With the light_client server producing only recent
 // updates it is okay to drop some events in case of overloading. In normal network conditions
@@ -15,7 +15,6 @@ pub async fn compute_light_client_updates<T: BeaconChainTypes>(
     chain: &BeaconChain<T>,
     mut light_client_server_rv: Receiver<LightClientProducerEvent<T::EthSpec>>,
     reprocess_tx: Sender<ReprocessQueueMessage>,
-    log: &Logger,
 ) {
     // Should only receive events for recent blocks, import_block filters by blocks close to clock.
     //
@@ -28,12 +27,12 @@ pub async fn compute_light_client_updates<T: BeaconChainTypes>(
         chain
             .recompute_and_cache_light_client_updates(event)
             .unwrap_or_else(|e| {
-                error!(log, "error computing light_client updates {:?}", e);
+                error!("error computing light_client updates {:?}", e);
             });
 
         let msg = ReprocessQueueMessage::NewLightClientOptimisticUpdate { parent_root };
         if reprocess_tx.try_send(msg).is_err() {
-            error!(log, "Failed to inform light client update"; "parent_root" => %parent_root)
+            error!(%parent_root,"Failed to inform light client update")
         };
     }
 }