Add Mice! game and associated tools

- Created gameinfo.xml for the Mice! game, detailing its description, release date, developer, and genre.
- Added mice.sh script to activate the conda environment and run the game.
- Implemented colorize_assets.py as a placeholder for future asset colorization functionality.
- Developed convert_audio.py to convert audio files to 8-bit unsigned format at 22100 Hz.
- Introduced maze.py for generating mazes using Depth First Search (DFS) with a graphical interface.
- Created resize_assets.py to resize PNG assets to 18x18 pixels and center them on a 20x20 canvas.

gameinfo.xml

@@ -0,0 +1,14 @@
+<?xml version='1.0' encoding='utf-8'?>
+<gameList>
+  <game>
+  <path>./mice.sh</path>
+  <name>Mice!</name>
+  <desc>Mice! is a strategic single‑player game where you place bombs and mines to exterminate rats before they reproduce out of control. It features randomly generated mazes (DFS), sprite-based graphics, and sound effects. Inspired by the classic Rats! for Windows 95, this version is written in Python and uses a lightweight custom engine with SDL‑style rendering.</desc>
+  <releasedate>20250818T000000</releasedate>
+  <developer>Matteo Benedetto</developer>
+  <publisher>Self-published</publisher>
+  <genre>Strategy, Puzzle, Action</genre>
+  <players>1</players>
+  <image>./cover.png</image>
+  </game>
+</gameList>