Features/Intel: Prepare for edk2-platforms CI

Fix some build issues with GCC5 targets
Add a Readme.md for AdvancedFeaturePkg
Add VS2019, CLANGPDB, and GCC5 build targets to Readme.md
for each feature

Cc: Sai Chaganty <rangasai.v.chaganty@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Cc: Liming Gao <gaoliming@byosoft.com.cn>
Cc: Eric Dong <eric.dong@intel.com>
Cc: Dandan Bi <dandan.bi@intel.com>
Signed-off-by: Isaac Oram <isaac.w.oram@intel.com>
Reviewed-by: Sai Chaganty <rangasai.v.chaganty@intel.com>