Add appdmg package provider which bypasses EULAs

Adds a provider for the package type which will installs DMGs that require a EULA to be accepted - `appdmg_eula`.

As the EULA could be one or more pages, echoing Y into _hdiutil_ doesn't always work. Instead this converts the DMG to UDTO format (DVD/CD-R master) then attaches the resultant CDR file, which doesn't have a EULA, and installs the application.

Tested and working with the lastest version of the Charles Proxy DMG which has a multipage EULA.