chore: split-out vault code from teepot in teepot-vault

Signed-off-by: Harald Hoyer <harald@matterlabs.dev>

crates/teepot-vault/src/json/mod.rs

@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright (c) 2023 Matter Labs
+
+//! Common types for the teepot JSON API
+
+#![deny(missing_docs)]
+#![deny(clippy::all)]
+
+pub mod http;
+pub mod secrets;