Bump linkerd/namerd docker image version

[nfisher]

At a high level this PR is making a few changes:

1. bumping linkerd to 1.7.0.
2. fixing the broken hello-world.yml.
3. make a single RBAC YAML file that can be applied to a cluster without a separate create NS command (arguably could be done for each class of config). Focused here because few modern clusters seem to exist without it.

[cpretzer]

thanks @nfisher I'll go through a couple of tests and make things run as expected. Then we merge!

[nfisher]

@cpretzer think it also needs to be synced with the docs sometimes the docs reference world and the name is world-v1 as an example.

[nfisher]

I'll submit a servicemesh-rbac.yml so there's a fully functioning RBAC example.

Currently the only example is copy and paste from this blog post with only the service account/role binding, etc in the example repo:
https://linkerd.io/2017/07/24/using-linkerd-kubernetes-rbac/

[adleong]

Did some quick spot checking and all of these appear to correctly start up with version 1.7.0

[cpretzer]

Changes all look straightforward. Thanks @nfisher