base: calculate initial junk based on 32/64 host

Issue #666
Add 'seoul_libc_support' library

This library contains the subset of the libc that is needed for the
Seoul VMM.

Related to issue #666.
Switch to Seoul VMM repository instead of NUL

In this version of the transition the Hip structure from Genode is reused,
@nfeskes seoul_libc_support is used for the string functions and the
nul/config.h is replaced by just using a constant value in the one place where
the file was needed.

Related to #666.
vancouver: correct framebuffer size.
vmm: try to reserve lower virtual address space

It's not guaranteed to be robust and will break in the future - I told you.

Related to issue #365, issue #519, issue #666
nova: show badge as name during page fault message
vancouver: calculate STACK_SIZE from addr_t size.

This is necessary on 64bit host.