BaseTools: Update edksetup.bat to support multiple workspaces

BaseTools: Update edksetup.bat to support multiple workspaces

1. Update edksetup.bat and toolsetup.bat to handle PACKAGES_PATH.
   BaseTools directory may be in PACKAGES_PATH instead of WORKSAPCE.
2. Introduce EDK_TOOLS_BIN env points to the windows binary tools dir.
   Windows BaseTools Win32 may be a separate directory.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Liming Gao <liming.gao@intel.com>
Reviewed-by: Wu Hao A <hao.a.wu@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@18582 6f19259b-4bc3-4df7-8a09-765794883524