Removing dependency on LauncherCallbacks for getting the search bounds

> Instead of handling insets in BaseContainerView, directly applying
  them to margins, as that scpace can't be used for scroll handling
> Appliying the top and bottom padding in xml
> The left & right padding is defied in xml which is reused for scroll
  handling

Bug: 27108154
Change-Id: Ia32e6d5e8fd1bfafb1d77d1244ce2268e4da9df9