Partially needed to avoid build breakages because Corrade itself
switched as well, partially because a cleanup is always good. Done
except for (STL-heavy) code that's deprecated or SceneGraph-related APIs
that are still quite full of STL as well.
Same as the previous commit in MeshTools -- allows to pass a
Containers::Array<DescriptorSetLayoutBinding> to it without having to
form a list of references first.
Together with DescriptorBindingFlags, because it affects the design in a
rather specific way and it wouldn't make sense to postpone this and
forget all again until it becomes needed.