BaseTools: Remove GenVtf

BaseTools: Remove GenVtf

GenVtf C tool is IPF specific. IPF support has been removed
from edk2 trunk. This tool can be removed.
https://bugzilla.tianocore.org/show_bug.cgi?id=1349

v2:Remove GenVtf in Makefile and GNUmakefile.

v3:Remove BinWrappers/PosixLike/GenVtf and the user manual
   of GenVtf.

Cc: Yonghong Zhu <yonghong.zhu@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Shenglei Zhang <shenglei.zhang@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>