SecurityPkg/OpalPassword: Add warning message for Secure Erase

SecurityPkg/OpalPassword: Add warning message for Secure Erase

https://bugzilla.tianocore.org/show_bug.cgi?id=1753
Add pop-up warning messages before secure erase action.
In order to notify user the secure erase action will take a longer time.
This change also fix some pop-up windows are unable to show up
complete message due to some strings are too long.

Signed-off-by: Maggie Chu <maggie.chu@intel.com>
Cc: Chao Zhang <chao.b.zhang@intel.com>
Cc: Jiewen Yao <jiewen.yao@intel.com>
Reviewed-by: Eric Dong <eric.dong@intel.com>