feat: adds convert_to_hex exercise

Author: flamiedev

convert_to_hex.py

@@ -0,0 +1,18 @@
+class Solution:
+    def toHex(self, num: int) -> str:
+        if num == 0:
+            return "0"
+        if num < 0:
+            num = (1 << 32) + num
+
+        hex_digits = "0123456789abcdef"
+
+        hex_num = ""
+
+        while num > 0:
+            digit = num % 16
+            hex_digit = hex_digits[digit]
+            hex_num = hex_digit + hex_num
+            num //= 16
+
+        return hex_num