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_010/sol1.py

@@ -0,0 +1,58 @@
+"""
+https://projecteuler.net/problem=10
+
+Problem Statement:
+The sum of the primes below 10 is 2 + 3 + 5 + 7 = 17.
+
+Find the sum of all the primes below two million.
+"""
+from math import sqrt
+
+
+def is_prime(n: int) -> bool:
+    """Returns boolean representing primality of given number num.
+    >>> is_prime(2)
+    True
+    >>> is_prime(3)
+    True
+    >>> is_prime(27)
+    False
+    >>> is_prime(2999)
+    True
+    """
+    for i in range(2, int(sqrt(n)) + 1):
+        if n % i == 0:
+            return False
+
+    return True
+
+
+def solution(n: int = 2000000) -> int:
+    """Returns the sum of all the primes below n.
+
+    # The code below has been commented due to slow execution affecting Travis.
+    # >>> solution(2000000)
+    # 142913828922
+    >>> solution(1000)
+    76127
+    >>> solution(5000)
+    1548136
+    >>> solution(10000)
+    5736396
+    >>> solution(7)
+    10
+    """
+    if n > 2:
+        sum_of_primes = 2
+    else:
+        return 0
+
+    for i in range(3, n, 2):
+        if is_prime(i):
+            sum_of_primes += i
+
+    return sum_of_primes
+
+
+if __name__ == "__main__":
+    print(solution(int(input().strip())))