fileutils: move API to std::filesystem, cleanup

Change-Id: I5408d193bda6830395bd705371c86c949643ee74
diff --git a/include/connectionmanager.h b/include/connectionmanager.h
index b03c345..b42b633 100644
--- a/include/connectionmanager.h
+++ b/include/connectionmanager.h
@@ -292,7 +292,7 @@
 
     std::shared_ptr<TurnCache> turnCache;
 
-    std::string cachePath {};
+    std::filesystem::path cachePath {};
 
     std::shared_ptr<asio::io_context> ioContext;
     std::shared_ptr<dht::DhtRunner> dht;