UefiPayloadPkg: Add PayloadLoaderPeim which can load ELF payload

UefiPayloadPkg: Add PayloadLoaderPeim which can load ELF payload

Per universal payload spec, the payload is in ELF format.
The patch adds a payload loader that supports to load ELF image.

The location of extra data sections whose names start with "upld."
is stored in UNIVERSAL_PAYLOAD_EXTRA_DATA HOB.

Signed-off-by: Maurice Ma <maurice.ma@intel.com>
Signed-off-by: Ray Ni <ray.ni@intel.com>
Cc: Maurice Ma <maurice.ma@intel.com>
Reviewed-by: Guo Dong <guo.dong@intel.com>
Cc: Benjamin You <benjamin.you@intel.com>