QemuOpenBoardPkg: Enable stage 4

Enable MinPlatform stage 4 (OS boot) functionality.
It adds ACPI, SMBIOS and SMM drivers required for stage 4.
This should boot Windows and Linux with PIIX4 or Q35 configurations.
In the current state, SMM only works on Qemu Q35 system if you set
SMM_REQUIRED = TRUE in QemuOpenBoardPkg.dsc or via command-line.

Cc: Leif Lindholm <quic_llindhol@quicinc.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Isaac Oram <isaac.w.oram@intel.com>
Cc: Pedro Falcato <pedro.falcato@gmail.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Stefan Hajnoczi <stefanha@gmail.com>
Signed-off-by: Theo Jehl <theojehl76@gmail.com>
Series Reviewed-by: Isaac Oram <isaac.w.oram@intel.com>
Acked-by: Michael D Kinney <michael.d.kinney@intel.com>
Series-Reviewed-by: Pedro Falcato <pedro.falcato@gmail.com>