feat: add function show_complex_color prints all avaiable colors

* This function prints all available colors with a number.
* Printed colors in the console **automatically adjust** to the size
of your window. You can shrink or enlarge the console window to
adjust the corresponding view.

This feature is just an example of the available colors that you can
use in your project.

There will be a function to use these colors soon.

src/mdsanima_dev/colors.py

@@ -0,0 +1,28 @@
+"""
+# Colors Module
+
+Definitions of the colors printed in to console output.
+"""
+
+
+def show_complex_color():
+    """
+    This function prints all available colors with a number.
+
+    Returns:
+        console_print: Show all colors.
+    Usage:
+    .. code::
+        show_complex_color()
+    """
+    # Define color console variables.
+    sx = '\x1b[38;5;'
+    ex = '\x1b[0m'
+
+    # Print all colors with numbers.
+    for i in range(255):
+        color = (sx + str(i) + 'm' + 'color ' + str(i+1).ljust(3) + ex)
+        print(color, sep = ' ', end = '   ', flush = True)
+
+    print('\n\nDONE')
+