BaseTools: Update FMP Capsule support to follow FDF spec

BaseTools: Update FMP Capsule support to follow FDF spec

Current the FMP Capsule feature is supported, but its format has a little
different with FDF spec. so this patch 1) Align the FMP Capsule with FDF
spec. 2) fix some style issue, eg: Tab. 3) Add a SectionParser function to
check the section header info since this method is used in 7 places.

Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Yonghong Zhu <yonghong.zhu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>