Bring the proc device back.

We can now view namespaces and such.
I'll extend this more to get us real info.

/ $ ls '#p'
1          trace      tracepids
/ $ cat '#p/1/ns'
cd /
/ $ ash /ifconfig
bind #c -> /dev flag 1
bind #p -> /proc flag 1
bind #s -> /srv flag 1
bind #I -> /net flag 2
bind #l0 -> /net flag 2
Incoming IRQ, ISR: 73 on core 0
I am 10.0.2.15, default route 10.0.2.2
/ $ cat '#p/1/ns'
bind  /dev /dev
bind -b #c /dev
bind  /srv /srv
bind -b #s /srv
bind  /net /net
bind -a #I /net
bind -a #l /net
cd /
/ $

Signed-off-by: Ronald G. Minnich <rminnich@google.com>