NetworkPkg/TlsAuthConfigDxe: Provide the UI to support TLS auth configuration

This patch provides the UI to support TLS auth configuration.
* EFI_SIGNATURE_LIST format is used for 'TlsCaCertificate'
variable. So, TLS supports multiple certificate configuration.
* The variable attribute is BS with NV, which only target at
preventing runtime phase attack.

Cc: Ye Ting <ting.ye@intel.com>
Cc: Fu Siyuan <siyuan.fu@intel.com>
Cc: Zhang Lubo <lubo.zhang@intel.com>
Cc: Long Qin <qin.long@intel.com>
Cc: Thomas Palmer <thomas.palmer@hpe.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Wu Jiaxin <jiaxin.wu@intel.com>
Reviewed-by: Fu Siyuan <siyuan.fu@intel.com>
Reviewed-by: Ye Ting <ting.ye@intel.com>