ldso: turn on object mapping message by default

Showing the object base map address always eases debugging. If Genode
is build in release mode, fall back to normal dbg definition.
dde_rump: add extended rump_fs server test.

The run-script includes the usage of part_blk, blk_cache, and ahci.
rump_fs: mount file system on-demand

The rumpkernel will now mount the specified file system on the first
session request. In addition it will be unmounted when the last client
closes its session. This way we make sure the used file system is
properly unmounted and all pending buffers are synced or rather flushed.
fixup exte