Fixed navigating by D-pad in Bookmark Manager

Fixed navigating by D-pad in Bookmark Manager

[Issue]    https://bugs.tizen.org/jira/browse/TT-183
[Problem]  There was a problem with navigation in Bookmark Manager.
[Cause]    Disabled "Add to bookmarks" button was blocking moving
           the focus.
[Solution] This is a workaround (because 'custom focus chain' API
           did not work properly. FocusManager class is used.
           Additionally, changed topContent from genlist to layout.
[Verify]   Launch browser > Navigate to Bookmarka Manager > Use arrows to
           move the focus.

Change-Id: I8f22bb24653f9df0dde5f5e009fbbd73d887d6ec