creates role::ci::{master,slave,website}

The role::jenkins::* classes are only suitable for Continuous
Integration since they rely on having a SSD on the box.  We also make
use of tmpfs which is probably never going to be used outside of CI.
Directly calling modules at node level is not very nice, so regroup
those calls under the new roles as well.

Here we phase out the role::jenkins::{master,slave} class in favor of
role::ci::{master,slave}.  The new roles take care of setting up a node
with all the contint specific dependencies such as:

- setting up jenkins workspace home with proper permissions
- creating a tmpfs
On master:
- Ganglia monitoring
- website setup + Zuul,Jenkins proxies
On slaves:
- Ssh key on for Jenkins master to connect to slaves
- contint::packages which is required to run tests
- Gerrit replication receiver

All CI executor (slaves and master)  nodes MUST have a /srv/ssd mounted.
This is enforced in the role::ci:: class by requiring a
Mount['/srv/ssd'].  The mount itself needs to be made at the node level
so we can install on a box both a master and a slave (that is the case
for gallium).

Change-Id: If3a4779af8c9de6bcbff01141e804a1d54f8e34c
Merge "creates role::ci::{master,slave,website}" into production