Move crates under a sub folder to clean up the code

crates/json-depth-checker/fuzz/fuzz_targets/depth.rs

@@ -0,0 +1,13 @@
+#![no_main]
+use arbitrary_json::ArbitraryValue;
+use json_depth_checker::*;
+use libfuzzer_sys::fuzz_target;
+
+fuzz_target!(|value: ArbitraryValue| {
+    let value = serde_json::Value::from(value);
+    let left = should_flatten_from_value(&value);
+    let value = serde_json::to_vec(&value).unwrap();
+    let right = should_flatten_from_unchecked_slice(&value);
+
+    assert_eq!(left, right);
+});