Readme/post-install warning feedback

[LukeWinikates]

We successfully installed concourse on a GKE cluster today.

Install warning feedback:

The post-install baggage claim driver feedback is useful, but the values.yml is so big that it's hard to track down the parent keys so that you can actually set it. (i.e. concourse.worker.baggageclaim.driver). That configuration value is not listed in the README page, which it probably should be if there's going to be a post-install warning about it. The key should probably be printed in the warning message to make it easy on users.

We also got this warning:

"You're using the default "test" user with the default "test" password."

I think this is spurious in our case, because we also set secrets.create: false. However we did find the code in the chart that was printing this, and realized we could set secrets.localUsers: "" to make the warning go away. I did confirm that test:test does not work on our helm deployed concourse.

README feedback

I found that the README section about secrets was inaccurate with respect to creating secrets for local users, github secrets, and the postgres username/password. The README indicates that you put these in the $HELM_RELEASE-concourse secret, but we found that we had to put them into the $HELM_RELEASE-web secret.