MdeModulePkg/UefiBootManagerLib: Enhance short-form expanding logic

MdeModulePkg/UefiBootManagerLib: Enhance short-form expanding logic

Old implementation only finds first matched full device path for a
given short-form device path.
The patch adds internal function BmGetNextLoadOptionBuffer() to finds
all matched full device path for a given short-form device path.
There are 6 kinds of device paths. Some of them match to multiple
load options, some of them don't.

1. Media device path:
   Returns multiple load options: The media device path may point
   to a physical BlockIo which contains multiple logic partitions,
   each logic partitions contains \EFI\BOOT\BOOT${ARCH}.EFI.

2. Short-form hard-drive device path:
   Returns one load option because the partition signature is unique.

3. Short-form file-path device path:
   Returns multiple load options: There are multiple SimpleFileSystem
   instances and each contains the same file.

4. Short-form URI device path:
   Returns multiple load options: There are multiple LoadFile
   instances and each can boot.

5. Short-form USB device path:
   Returns multiple load options: There are multiple UsbIo instances
   and each contains the boot-able file.

6. FV device path, device path pointing to SimpleFileSystem, device
   path pointing to LoadFile
   Returns one load option.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Jeff Fan <jeff.fan@intel.com>