Refactor charts to use Helm Tags and Condition fields

[mboersma]

Currently some Workflow components such as minio are conditionally disabled by enclosing all their manifest templates in {{ if }} blocks, because that was the only way to have Helm avoid installing a sub-chart. This is ugly and feels wrong when considering that most component sub-charts are also meant to stand alone.

Now Helm supports tags and conditions in requirements.yaml, a much cleaner way to accomplish this functionality. If it can be done in a backward-compatible way, we should refactor all relevant sub-charts to use this mechanism, and require Workflow users to install with helm v2.2.1 or later.

See related discussion at https://github.com/deis/router/pull/316#discussion_r104589994.

[bacongobbler]

For lots of the components we check if the field is either the string "on-cluster" or "off-cluster". That may be hard to work around since the conditional fields are supposed to be booleans.

[krisnova]

I ran into the same problem https://github.com/deis/router/pull/316#discussion_r104589994 when I first drafted the chart. Luckily I was able to restructure the values so that we could use a bool

But to be honest it would be nice if helm supported conditional inclusions based on more than just bools. I think a string compare (or even regex!) would fit in nicely.