Add parse_orientation()

This function parse a char and return the matching direction or None

src/main.rs

@@ -11,6 +11,16 @@ enum Instruction {
     F,
 }
 
+fn parse_orientation(c: char) -> Option<Orientation> {
+    match c {
+        'N' => Some(Orientation::N),
+        'E' => Some(Orientation::E),
+        'S' => Some(Orientation::S),
+        'W' => Some(Orientation::W),
+        _ => None,
+    }
+}
+
 fn main() {
     let file_data = include_str!("../two_robots.txt");
 }