Add Day 3, Puzzle 2 solution

- Implement generalized function for Puzzle 2
    - Use generalized function also for Puzzle 1

src/Main.hs

@@ -2,7 +2,7 @@ module Main (main) where
 
 import Day01 (day01_1, day01_2)
 import Day02 (day02_1, day02_2)
-import Day03 (day03_1)
+import Day03 (day03_1, day03_2)
 import System.Environment (getArgs)
 
 main :: IO ()
@@ -20,12 +20,15 @@ main = do
       day02_1
       day02_2
     "3" : "1" : _ -> day03_1
+    "3" : "2" : _ -> day03_2
     "3" : _ -> do
       day03_1
+      day03_2
     "all" : _ -> do
       day01_1
       day01_2
       day02_1
       day02_2
       day03_1
+      day03_2
     _ -> error "Not implemented"