refactor: route remaining external storage boundaries (#3889)

fuzz/fuzz_targets/path_containment.rs

@@ -1,9 +1,8 @@
 #![no_main]
 
 use libfuzzer_sys::fuzz_target;
-use rustfs_ecstore::api::bucket::utils::{
-    check_object_name_for_length_and_slash, has_bad_path_component, is_valid_object_prefix,
-};
+mod path_containment_storage_api;
+use path_containment_storage_api::{check_object_name_for_length_and_slash, has_bad_path_component, is_valid_object_prefix};
 use rustfs_utils::path::{clean, path_join};
 use std::path::{Path, PathBuf};