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/http_metrics/tests/tests.rs

@@ -1,6 +1,6 @@
 use beacon_chain::test_utils::EphemeralHarnessType;
 use http_metrics::Config;
-use logging::test_logger;
+use logging::create_test_tracing_subscriber;
 use reqwest::header::HeaderValue;
 use reqwest::StatusCode;
 use std::net::{IpAddr, Ipv4Addr};
@@ -12,9 +12,8 @@ type Context = http_metrics::Context<EphemeralHarnessType<MainnetEthSpec>>;
 
 #[tokio::test(flavor = "multi_thread", worker_threads = 2)]
 async fn returns_200_ok() {
+    create_test_tracing_subscriber();
     async {
-        let log = test_logger();
-
         let context = Arc::new(Context {
             config: Config {
                 enabled: true,
@@ -27,7 +26,6 @@ async fn returns_200_ok() {
             db_path: None,
             freezer_db_path: None,
             gossipsub_registry: None,
-            log,
         });
 
         let ctx = context.clone();