ui/crumbs/tasklistmodel: ignore tasks and images when marking dependencies

ui/crumbs/tasklistmodel: ignore tasks and images when marking dependencies

When calculating what dependencies are affected by the removal of an item
we should ignore images and tasks as they are not constructs which make
sense in the GUI.
E.g: if we don't ignore tasks and remove opkg from an image based on
core-image-minimal the fact that opkg was brought in by task-core results
in task-core and all of the packages it brought in being removed and,
eventually, an empty image.

(Bitbake rev: 205b52bfc7f28af0c50fef1f741fae6af16fb0dc)

Signed-off-by: Joshua Lock <josh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>