Added cache for get role secret (#6165)

## Problem

Currently if we are getting many consecutive connections to the same
user/ep we will send a lot of traffic to the console.

## Summary of changes

Cache with ttl=4min proxy_get_role_secret response.

Note: this is the temporary hack, notifier listener is WIP.

proxy/src/auth/backend.rs

@@ -9,7 +9,6 @@ use tokio_postgres::config::AuthKeys;
 use crate::auth::credentials::check_peer_addr_is_in_list;
 use crate::auth::validate_password_and_exchange;
 use crate::console::errors::GetAuthInfoError;
-use crate::console::provider::AuthInfo;
 use crate::console::AuthSecret;
 use crate::proxy::connect_compute::handle_try_wake;
 use crate::proxy::retry::retry_after;
@@ -187,17 +186,13 @@ async fn auth_quirks(
     };
 
     info!("fetching user's authentication info");
-    // TODO(anna): this will slow down both "hacks" below; we probably need a cache.
-    let AuthInfo {
-        secret,
-        allowed_ips,
-    } = api.get_auth_info(extra, &info).await?;
+    let allowed_ips = api.get_allowed_ips(extra, &info).await?;
 
     // check allowed list
     if !check_peer_addr_is_in_list(&info.inner.peer_addr, &allowed_ips) {
         return Err(auth::AuthError::ip_address_not_allowed());
     }
-    let secret = secret.unwrap_or_else(|| {
+    let secret = api.get_role_secret(extra, &info).await?.unwrap_or_else(|| {
         // If we don't have an authentication secret, we mock one to
         // prevent malicious probing (possible due to missing protocol steps).
         // This mocked secret will never lead to successful authentication.