Added get_languages(), detect_language() functions and test cases for th...

*Added the get_languages() function to get a Python list of the supported language locale codes.
*Added detect_language() function to detect the language of the input text.
*Added test cases for both functions - Test cases pass with no failures.
Like the idea of using set subsets. There is a shortcut instead of comparing with `True`

`self.assertTrue(set(default_languages).issubset(set(languages)))`