Rename Project Euler directories and other dependent changes (#3300)

* Rename all Project Euler directories:

Reason:
The change was done to maintain consistency throughout the directory
and to keep all directories in sorted order.

Due to the above change, some config files had to be modified:
'problem_22` -> `problem_022`

* Update scripts to pad zeroes in PE directories

project_euler/problem_024/sol1.py

@@ -0,0 +1,27 @@
+"""
+A permutation is an ordered arrangement of objects. For example, 3124 is one
+possible permutation of the digits 1, 2, 3 and 4. If all of the permutations
+are listed numerically or alphabetically, we call it lexicographic order. The
+lexicographic permutations of 0, 1 and 2 are:
+
+    012   021   102   120   201   210
+
+What is the millionth lexicographic permutation of the digits 0, 1, 2, 3, 4, 5,
+6, 7, 8 and 9?
+"""
+from itertools import permutations
+
+
+def solution():
+    """Returns the millionth lexicographic permutation of the digits 0, 1, 2,
+    3, 4, 5, 6, 7, 8 and 9.
+
+    >>> solution()
+    '2783915460'
+    """
+    result = list(map("".join, permutations("0123456789")))
+    return result[999999]
+
+
+if __name__ == "__main__":
+    print(solution())