binarycreator: add qico and qtaccessiblewidgets as QTPLUGINs

Commit 807de076f4fee6c relies on the autoplugs mechanism (added in
qtbase commit 4255ba40ab073af) to add the needed statically linked
plugins; however because binarycreator is a console app it doesn't
depend on gui (QT -= gui) this mechanism fails to add the plugins.

Change-Id: If96b0e2c03d229ad1026602b8e8117babda03481
Reviewed-by: Niels Weber <niels.weber@digia.com>
Reviewed-by: Karsten Heimrich <karsten.heimrich@digia.com>