Move crates under a sub folder to clean up the code

crates/json-depth-checker/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "json-depth-checker"
+description = "A library that indicates if a JSON must be flattened"
+publish = false
+
+version.workspace = true
+authors.workspace = true
+# description.workspace = true
+homepage.workspace = true
+readme.workspace = true
+edition.workspace = true
+license.workspace = true
+
+[dependencies]
+serde_json = "1.0"
+
+[dev-dependencies]
+criterion = "0.5.1"
+
+[[bench]]
+name = "depth"
+harness = false