This allows `-cpu host` in KVM

closes https://github.com/acidanthera/bugtracker/issues/1950

- Add support for .contentFlavour and .contentDetails
- Add LINUX_BOOT_ADD_RW flag
- Add flags+= and flags-=
- Fixed entry name disambiguation when LINUX_BOOT_USE_LATEST is unset

(safe after d5144240, which fixes behaviour of CSR_ALLOW_APPLE_INTERNAL)

closes #312
closes acidanthera/bugtracker#1899

 - Fix broken in-OS sound in Windows after AudioDxe with some firmware (closes https://github.com/acidanthera/bugtracker/issues/1909)
 - Add Pcds for some AudioDxe code
 - Other minor updates
OcDebugLogLib:
 - Add DebugPrintDevicePathForHandle

AudioDxe: Improve documentation and logging of AudioOutMask, and change default value to 'output all'

 - DisconnectHda
 - AudioOutRange
 - Cirrus Logic (Apple) and QEMU fixes
 - Other fixes

references acidanthera/bugtracker#1888

OcBootManagementLib: Extend ProtectUefiServices quirk to restore hooks overwritten by GRUB2 shim as required

closes acidanthera/bugtracker#1717