UefiPayloadPkg: Make Boot Manager Key configurable

Provide a build option to use [Esc] instead of [F2] for devices
such as Chromebooks that don't have F-keys.

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

UefiPayloadPkg/UefiPayloadPkg.dsc

@@ -34,6 +34,7 @@
   DEFINE SECURITY_STUB_ENABLE         = TRUE
   DEFINE SMM_SUPPORT                  = FALSE
   DEFINE ABOVE_4G_MEMORY              = TRUE
+  DEFINE BOOT_MANAGER_ESCAPE          = FALSE
   #
   # SBL:      UEFI payload for Slim Bootloader
   # COREBOOT: UEFI payload for coreboot
@@ -401,6 +402,7 @@
 !endif
 
   gUefiPayloadPkgTokenSpaceGuid.PcdDispatchModuleAbove4GMemory|$(ABOVE_4G_MEMORY)
+  gUefiPayloadPkgTokenSpaceGuid.PcdBootManagerEscape|$(BOOT_MANAGER_ESCAPE)
 
 [PcdsPatchableInModule.X64]
   gPcAtChipsetPkgTokenSpaceGuid.PcdRtcIndexRegister|$(RTC_INDEX_REGISTER)