ShellPkg: Fixes and updates for the 'drivers' command

ShellPkg: Fixes and updates for the 'drivers' command
- Update 'drivers -sfo' format to match UEFI Shell 2.1 spec
- Update help output for easier viewing
- Update 'drivers' output format for better alignment
             T   D
             Y C I
             P F A
DRV VERSION  E G G #D  #C  DRIVER NAME                         IMAGE PATH
=== ======== = = = === === =================================== ==========

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Chris Phillips <chrisp@hp.com>
Reviewed-by: Jaben Carsey <jaben.carsey@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15870 6f19259b-4bc3-4df7-8a09-765794883524