Add jupyterhub-idle-culler to jupyterhub image

[danlester]

Fixes #958
Fixes #960
Fixes #961

Changes:

• Add jupyterhub-idle-culler to jupyterhub image's environment
• Fixes Jupyterhub Helm upgrades wait indefinitely
• Solves project field no longer needed for azure in qhub-config

Types of changes

What types of changes does your code introduce?

Put an x in the boxes that apply

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds a feature)
• Breaking change (fix or feature that would cause existing features to not work as expected)
• Documentation Update
• Code style update (formatting, renaming)
• Refactoring (no functional changes, no API changes)
• Build related changes
• Other (please describe):

Testing

Requires testing

• Yes
• No

In case you checked yes, did you write tests?

• Yes
• No

Further comments (optional)

Starting this branch should build the image then I will test it.

[tylerpotts]

LGTM