Vlv2TbltDevicePkg/PlatformBootManager: Add capsule/recovery handling.

Vlv2TbltDevicePkg/PlatformBootManager: Add capsule/recovery handling.

1) Add capsule and recovery boot path handling in platform BDS.
2) Add check if the platform is using default test key for capsule.
Produce PcdTestKeyUsed to indicate if there is any
test key used in current BIOS, such as recovery key,
or capsule update key.
Then the generic UI may consume this PCD to show warning information.

Cc: David Wei <david.wei@intel.com>
Cc: Feng Tian <feng.tian@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Chao Zhang <chao.b.zhang@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: David Wei <david.wei@intel.com>