Duplicate method on LightweightActivity

[#49085561] This is the first step, just copying non-association attributes.
show_interactive assignment should handle true

This was set up earlier to manage additional actions when show_interactive was changed, but it kept me from actually using booleans in assignment.
Duplicating InteractivePage instances

[#49085561]
Pages are copied with activities

[#49085561]
Copying interactives [#49085561]
Refactoring dupe first steps
Duplicate-able Embeddables [#49085561]
Pages duplicate their embeddables and interactives

[#49085561] This should finish duplication.
We really only need to fix the name for the activity

Tweaking the page names is only going to be annoying.
Check that the new activity name isn't too long

Adding "Copy of " to the title string can sometimes make it longer than we allow, thus blocking saving of the new activity. [#49085561]
Controller action for duplicating activities.

[#49085561]
Add "copy" link to activity index

[#49085561]
Merge branch 'refs/heads/master' into duplicate-activities
Tweaking width to fit the copy button
Merge branch 'refs/heads/master' into duplicate-activities
Disambiguating permissions on index page
Better confirmation of page ordering in copy
Trapping for nils
Fixing up duplication specs