Refactored some commands into FileHandleLib since they are used in many binaries.
Added .h for GUID that was missing.
Added PCD for initialization of shell apps and shell itself in shell library interaction.
git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@8295 6f19259b-4bc3-4df7-8a09-765794883524