Add basic USB CDROM support via USB MSC

[i-am-shodan]

Describe the PR
USB CDROM support requires that the SCSI INQUIRY command returns a different device type and qualifier. The current API for MSC devices doesn't allow the caller to influence these or appear as any other device type. This PR adds a new API function tud_msc_scsi_device_type(uint8_t lun) that enables expandability of SCSI device types as well as two new commands SCSI_CMD_READ_TOC and SCSI_CMD_READ_DISC_INFO.

In order to appear as a CDROM the caller must:

• Implement tud_msc_scsi_device_type and return MSC_SCSI_DEVICE_CDROM
• Implement SCSI_CMD_READ_TOC in tud_msc_scsi_cb (this returns the CDROM table of contents)
• Implement SCSI_CMD_READ_DISC_INFO in tud_msc_scsi_cb which returns disc info - in many cases this can be uint8_t[2] = {0}

This is a breaking change if you are currently using MSC and you're getting a compilation error you'll need to add.

msc_scsi_device_type_t tud_msc_scsi_device_type(uint8_t lun)
{
  (void) lun;
  return MSC_SCSI_DEVICE_BLOCK;
}