python-rpds-py: Add new package

From the README:

Python bindings to the Rust rpds crate for persistent data structures.

Signed-off-by: Jeffery To <jeffery.to@gmail.com>

lang/python/python-rpds-py/test.sh

@@ -0,0 +1,21 @@
+#!/bin/sh
+
+[ "$1" = python3-rpds-py ] || exit 0
+
+python3 - << 'EOF'
+
+from rpds import HashTrieMap, HashTrieSet, List
+
+m = HashTrieMap({"foo": "bar", "baz": "quux"})
+assert m.insert("spam", 37) == HashTrieMap({"foo": "bar", "baz": "quux", "spam": 37})
+assert m.remove("foo") == HashTrieMap({"baz": "quux"})
+
+s = HashTrieSet({"foo", "bar", "baz", "quux"})
+assert s.insert("spam") == HashTrieSet({"foo", "bar", "baz", "quux", "spam"})
+assert s.remove("foo") == HashTrieSet({"bar", "baz", "quux"})
+
+L = List([1, 3, 5])
+assert L.push_front(-1) == List([-1, 1, 3, 5])
+assert L.rest == List([3, 5])
+
+EOF