NetworkPkg: Remove DNS QType and QClass definition

NetworkPkg: Remove DNS QType and QClass definition

This patch is used to remove DNS QType and QClass definition in
DnsImpl.h since it will be exposed in NetLib.h.

Cc: Hegde Nagaraj P <nagaraj-p.hegde@hpe.com>
Cc: Ye Ting <ting.ye@intel.com>
Cc: Fu Siyuan <siyuan.fu@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jiaxin Wu <jiaxin.wu@intel.com>
Reviewed-by: Hegde Nagaraj P <nagaraj-p.hegde@hpe.com>
Reviewed-by: Ye Ting <ting.ye@intel.com>
Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>
git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19643 6f19259b-4bc3-4df7-8a09-765794883524