whitespace gardening.
Anonymous users cannot edit existing modules.

This implements the canImportModule property on the session object and
hides the button if the user does not have the relevant right.
Skip new/existing popup when in anon mode.
Factor workspace logic into the session.
Hide workspace selection for anonymous
Why is this here in the first place?

There is a bit of javascript that removes the disabled attr on the
upload button. It does not appear to be disabled to begin with, and
it makes it impossible to legitimately disable the button.
jquery's prop() method is better for disabled.

Better than using attr at least.
If get_next_action is None, disable the next button.
Disable the Finish button for anonymous users.