Increase the number of listvars

[#1]

Description -

Why is this feature important to you - We would like to leverage the capabilities of a list var for reporting across more dimensions as it helps our reporting community to evaluate content ownership questions when there is a one to many reporting or vic versa.

How would you like the feature to work - Ideally like list props, it would be great to have an enable option to convert an evar to a list var. However, if that's not possible, it would be great to increase the number of list vars available.

Current behaviour - There are currently only 3 list vars available.