userportal, webadmin: Instance-specific EditorDriver usage

This patch replaces static EditorDriver usage (public static
final field declared within specific Driver interface) with
instance-specific usage via private final field.

For non-singleton classes, using single static EditorDriver
instance can lead to problems, due to generated EditorDriver
implementation being stateful in its nature - initialize()
method binds the EditorDriver instance to given root Editor
(View).

This patch attempts to preserve natural ordering of View
class members where possible, from top to bottom:
* nested type declarations
* @UiField fields
* other fields
* constructor and methods

This patch also adds 'final' or 'private' to some fields,
as appropriate.

Change-Id: I73ba1fa29629538d6160fa042113859a6bf1ae7f
Signed-off-by: Alexander Wels <awels@redhat.com>
Signed-off-by: Vojtech Szocs <vszocs@redhat.com>