Previously every deployment (even just for a single tag, such as
`ansible-playbook site.yml --tags landingpage`) would have the caddy
deployment in its dependency.
That meant in effect whenever there was an updated caddy image, the role
would update it and we would lose all previous caddy configuration -
which in turn would necessitate a complete redeploymnet of all steps.
This is now not the case anymore.
Added caddy as swarm container. Uses templated Caddyfile which can be
set up for testing purposes for now.
Depends on docker and docker-swarm, and will keep its stuff where
docker-swarm sets itself up.
