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_042/solution42.py

@@ -0,0 +1,47 @@
+"""
+The nth term of the sequence of triangle numbers is given by, tn = ½n(n+1); so
+the first ten triangle numbers are:
+
+1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...
+
+By converting each letter in a word to a number corresponding to its
+alphabetical position and adding these values we form a word value. For example,
+the word value for SKY is 19 + 11 + 25 = 55 = t10. If the word value is a
+triangle number then we shall call the word a triangle word.
+
+Using words.txt (right click and 'Save Link/Target As...'), a 16K text file
+containing nearly two-thousand common English words, how many are triangle
+words?
+"""
+import os
+
+# Precomputes a list of the 100 first triangular numbers
+TRIANGULAR_NUMBERS = [int(0.5 * n * (n + 1)) for n in range(1, 101)]
+
+
+def solution():
+    """
+    Finds the amount of triangular words in the words file.
+
+    >>> solution()
+    162
+    """
+    script_dir = os.path.dirname(os.path.realpath(__file__))
+    wordsFilePath = os.path.join(script_dir, "words.txt")
+
+    words = ""
+    with open(wordsFilePath, "r") as f:
+        words = f.readline()
+
+    words = list(map(lambda word: word.strip('"'), words.strip("\r\n").split(",")))
+    words = list(
+        filter(
+            lambda word: word in TRIANGULAR_NUMBERS,
+            map(lambda word: sum(map(lambda x: ord(x) - 64, word)), words),
+        )
+    )
+    return len(words)
+
+
+if __name__ == "__main__":
+    print(solution())