Add the Diskpart utility by Lee Schroeder (milawynsrealm).

Add the Diskpart utility by Lee Schroeder (milawynsrealm).
The following modifications were made:
- Removed the help texts because they were copied from Windows Diskpart.
- Used a single string resource per help text.
- Used only Unicode strings and Unicode string functions.
- Replaced the giant if-statement in the command dispatcher in interpreter.c by a command-table and a little loop.
- Improved the command-line parser. Argument count and argument vector are passed to the command and help functions for easy evaluation.
- Moved the help function for commands into the command specific file.

TODO:
- Implement all commands as the utility is only an empty frame.
- Add help texts.
- Translate help texts.
See issue #6402 for more details.

svn path=/trunk/; revision=53826