Larger disk means more IO performance.
Require more CPUs to aid mksquashfs performance.
Signed-off-by: Miroslav Vadkerti <mvadkert@redhat.com>
(cherry picked from commit 067338f7db3ca39a7ba5677c4d8fea33f827e758)
In preparation for having multiple top-level kiwi description files,
expose the ability to define which file to read.
Additionally, tests are updated to use this new flag.