task-core: split into task-core-console and task-core-x11

task-core: split into task-core-console and task-core-x11

[YOCTO #1481]

Since tasks are referred to almost exclusively via RDEPENDS, and bitbake
will build an entire task recipe when only one of its task packages are
actually needed, building a console-only image that uses
task-core-apps-console (or less directly, has apps-console in its
IMAGE_FEATURES) will cause a build of a whole list of X11 applications
that aren't needed. Splitting the task-core recipe into X11 and console
portions prevents this issue.

(From OE-Core rev: 07407baafb728c5ae1bb283f5b02a2ac773360bc)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>