pragma once and for all

Fix licenses

Rationalise dependencies.

This commit removes the dependency of libsel4platsupport on
libsel4utils, as libsel4utils is our top level library and should be
able to use the device drivers that libsel4platsupport provides.

The functionality that libsel4platsupport depended on from libsel4utils
has been moved to libsel4simple, as libsel4simple is basically an
extension of libsel4.

libsel4utils: Import page.h definitions from libutils

The page sizes supported by a system are a combination of both the
raw architecture, as well as how seL4 is configured. This makes these
definitions system specific, hence the need to move them

As a consequence of having these defined in libsel4utils it is no
longer possible for libsel4vspace to use them, as libsel4utils
already depends upon libsel4vspace, and we do not support dual
dependencies in the build system. To compensate these checks are
added to the vspace implementation in libsel4utils