UI enhancements

- Show PrivatePermission Icon in PermissionWidget
- Remove unused PrivateDatum from PreferencePage
- new PrivateDatum defined: Machine ID
- Improve descriptions of PreferencePage/Popup Dialog
- Externalize strings

Change-Id: Icf1952364beb354ce04feb271884162533084302
Signed-off-by: Yasser Aziza <yasser.aziza@gmail.com>
Bug 437364: add Link to preference page from approval dialog

Change-Id: Ie8db98b7c657e8a08b8753a107ca97bf7d45b61b
Signed-off-by: Yasser Aziza <yasser.aziza@gmail.com>
Signed-off-by: Andreas Sewe <andreas.sewe@codetrails.com>