Add charmstore helm chart

[cmars]

I'd like to start developing & testing against JAAS services more easily. For Omnibus I've found this is much easier to set up and manage with Docker containers running in microk8s, than using mojo, or the ad-hoc pile of Makefiles, charms and scripts that is omnibus-layers, or trying to build everything from scratch and run manually, juggling local ports and config.

To deploy charmstore on microk8s with this branch:

• Run charts/scripts/sysdeps.bash
• make docker-push
• helm install ./charts/charmstore

Once all pods are up (kubectl get all), charmstore will be accessible at curl -H 'Host: jaas.local' localhost/charmstore/debug/info, etc. Edit /etc/hosts and then you won't need to set the header.

I've got similar PRs into Omnibus (CanonicalLtd/omnibus#1698) and Terms (CanonicalLtd/terms-service#151). My goal is to be able to run any subset of JAAS in microk8s on a laptop.

[jujugui]

Refer to this link for build results (access rights to CI server needed): http://ci-gce.jujugui.org:8080//job/charmstore/2255/

[jujugui]

Refer to this link for build results (access rights to CI server needed): http://ci-gce.jujugui.org:8080//job/charmstore/2256/

[jujugui]

Refer to this link for build results (access rights to CI server needed): http://ci-gce.jujugui.org:8080//job/charmstore/2257/

[jujugui]

Refer to this link for build results (access rights to CI server needed): http://ci-gce.jujugui.org:8080//job/charmstore/2258/