MdeModulePkg/CapsuleApp: Center bitmap at bottom of screen

MdeModulePkg/CapsuleApp: Center bitmap at bottom of screen

https://bugzilla.tianocore.org/show_bug.cgi?id=907

When -G option is used to convert a BMP file to a UX capsule,
the bitmap is centered horizontally and placed in the lower
half of the screen below the boot logo.

This matches examples shown in the following pages:

https://docs.microsoft.com/en-us/windows-hardware/drivers/bringup/user-experience-for-uefi-firmware-updates
https://docs.microsoft.com/en-us/windows-hardware/drivers/bringup/boot-screen-components

Checks are also made to make sure the bitmap provided
fits in the current GOP mode.

Cc: Jiewen Yao <jiewen.yao@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Reviewed-by: Jiewen Yao <jiewen.yao@intel.com>