Add 'createdvd' support

[so-knackered]

The scripts assume the CHD files were created using 'createcd' which is normally the case except some recent developments over the past 2 years:

1. Much of the PS2 community is moving to 'createdvd' for some better compression, although AetherSX2 for Android has not been updated for some time so it still requires CHD files be created using 'createcd'. Since both can be used to create these files depending for which emulator use, the script could perhaps dump the meta data of the file see which was used to create the CHD then use extractcd or extractdvd argument as necessary.
2. This also applies to PSP games, as PPSSPP now supports CHD files. These seem to be specifically optimized for best performance using createdvd