add load json

src/thd_json/load_json.py

+import json
+from pathlib import Path
+
+
+def load_thd_projection(json_path: Path):
+    if not json_path.suffix.endswith("json"):
+        raise ValueError("Wrong data type. Input must be `.json`file.")
+    meta_data = json.load(json_path.open())
+    return meta_data
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