Update and rename lca.py to lowest_common_ancestor.py (TheAlgorithms#1664)

* Update and rename lca.py to lowest_common_ancestor.py

* fixup! Format Python code with psf/black push

Author: cclauss

data_structures/binary_tree/lca.py renamed to data_structures/binary_tree/lowest_common_ancestor.py

@@ -1,3 +1,6 @@
+# https://en.wikipedia.org/wiki/Lowest_common_ancestor
+# https://en.wikipedia.org/wiki/Breadth-first_search
+
 import queue