MdeModulePkg: Add a pcd to set the OS indications bit

MdeModulePkg: Add a pcd to set the OS indications bit

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=1678

Add a pcd PcdPlatformRecoverySupport to conditionally
set an OS indications bit and set the 'PlatformRecovery####'
variable. This pcd would also control whether the BDS
support platform recovery or not.
Update the uni file to add the prompt and help string base on
the description in dec file.

Cc: Jian J Wang <jian.j.wang@intel.com>
Cc: Hao Wu <hao.a.wu@intel.com>
Cc: Ray Ni <ray.ni@intel.com>
Cc: Star Zeng <star.zeng@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Sean Brogan <sean.brogan@microsoft.com>
Cc: Michael Turner <Michael.Turner@microsoft.com>
Cc: Bret Barkelew <Bret.Barkelew@microsoft.com>
Signed-off-by: Zhichao Gao <zhichao.gao@intel.com>
Reviewed-by: Ray Ni <ray.ni@intel.com>
Reviewed-by: Hao A Wu <hao.a.wu@intel.com>