Restructure hub template doc, update diagram and add more info

[GeorgianaElena]

Ref: #274
Closes #162

[yuvipanda]

One comment, but text looks good! The image is empty?

[yuvipanda]

In addition, I think we need to document https://github.com/2i2c-org/pilot-hubs/blob/master/hub.py#L356. If you're using daskhub or ephemeral hub, config in hubs.yaml needs to be nested under a base-hub key. This is because base-hub is now a sub chart of daskhub, and jupyterhub (z2jh) is a sub chart of base-hub (https://helm.sh/docs/chart_template_guide/subcharts_and_globals/#overriding-values-from-a-parent-chart). Does this make sense?

[GeorgianaElena]

The image is empty?

It shouldn't be: https://github.com/GeorgianaElena/pilot-hubs/blob/docs/hub-templates/docs/images/config-flow.png

Does this make sense?

Yes! Ty!

[yuvipanda]

Ah, GitHub shows the images like this:

But they're clearly there!

And they're pretty damn awesome! I'll merge this now :)

[choldgraf]

@GeorgianaElena can you add a comment in these docs (with % ) that says where these images were created, and how a different team member could update them if they wanted to do so?