major msg -> obj file transfer refactor

mostly done, some things are hacky or not done

solanaceae/tox_messages/backends/tox_ft_filesystem.hpp

@@ -0,0 +1,19 @@
+#pragma once
+
+#include <solanaceae/object_store/object_store.hpp>
+
+namespace Backends {
+
+struct ToxFTFilesystem : public StorageBackendI {
+	ToxFTFilesystem(
+		ObjectStore2& os
+	);
+	~ToxFTFilesystem(void);
+
+	ObjectHandle newObject(ByteSpan id) override;
+
+	std::unique_ptr<File2I> file2(Object o, FILE2_FLAGS flags) override;
+};
+
+} // Backends
+