Re-organize directory structure (#4971)

See discussion in #2491

Co-authored-by: Ivan Levkivskyi <ilevkivskyi@dropbox.com>

stubs/ujson/ujson.pyi

@@ -0,0 +1,35 @@
+from typing import IO, Any, AnyStr
+
+__version__: str
+
+def encode(
+    obj: Any,
+    ensure_ascii: bool = ...,
+    double_precision: int = ...,
+    encode_html_chars: bool = ...,
+    escape_forward_slashes: bool = ...,
+    sort_keys: bool = ...,
+    indent: int = ...,
+) -> str: ...
+def dumps(
+    obj: Any,
+    ensure_ascii: bool = ...,
+    double_precision: int = ...,
+    encode_html_chars: bool = ...,
+    escape_forward_slashes: bool = ...,
+    sort_keys: bool = ...,
+    indent: int = ...,
+) -> str: ...
+def dump(
+    obj: Any,
+    fp: IO[str],
+    ensure_ascii: bool = ...,
+    double_precision: int = ...,
+    encode_html_chars: bool = ...,
+    escape_forward_slashes: bool = ...,
+    sort_keys: bool = ...,
+    indent: int = ...,
+) -> None: ...
+def decode(s: AnyStr, precise_float: bool = ...) -> Any: ...
+def loads(s: AnyStr, precise_float: bool = ...) -> Any: ...
+def load(fp: IO[AnyStr], precise_float: bool = ...) -> Any: ...