examples: add the example from projects/logging

This simplifies the example by adding a service which writes to the
log every 1s and a getty for introspection.

To see the logs:

  /proc/1/root/usr/bin/logread -F

Signed-off-by: David Scott <dave.scott@docker.com>

projects/logging/examples/logging.yml

@@ -1,33 +0,0 @@
-kernel:
-  image: linuxkit/kernel:4.14.53
-  cmdline: "console=ttyS0 console=tty0 page_poison=1"
-init:
-  - linuxkit/init:0e4af96fecc8f752c80d41c0b7d06570cc1dc6b2
-  - linuxkit/runc:v0.4
-  - linuxkit/containerd:27a4c84cc8fab2d5ea04342546ecd20453ec99b3
-  - linuxkit/ca-certificates:v0.4
-  - linuxkit/memlogd:4c16d6720075bcb2aeb298a8ee2d08d74aa20512
-onboot:
-  - name: sysctl
-    image: linuxkit/sysctl:v0.4
-  - name: dhcpcd
-    image: linuxkit/dhcpcd:1fe0db6b1eb7bcb1e4823e61e08afe6d48af7d16
-    command: ["/sbin/dhcpcd", "--nobackground", "-f", "/dhcpcd.conf", "-1"]
-services:
-  - name: rngd
-    image: linuxkit/rngd:v0.4
-  - name: nginx
-    image: nginx:1.13.8-alpine
-    capabilities:
-     - CAP_NET_BIND_SERVICE
-     - CAP_CHOWN
-     - CAP_SETUID
-     - CAP_SETGID
-     - CAP_DAC_OVERRIDE
-files:
-  - path: etc/docker/daemon.json
-    contents: '{"debug": true}'
-trust:
-  org:
-    - linuxkit
-    - library