Add descriptive text to Workload Balancer default filter

[#1]

Description - To better guide users in choosing filters, a description helps. Currently, even an admin can't update the Description of the Default filter.

Why is this feature important to you - Defaults can be useful in streamlining administrative load because that means I don't have to make something if it already exists and meets our needs. 

How would you like the feature to work - Show a description of the filter so users can better assess when to apply the Default filter.

Current Behaviour - There is no description associated with the Default filter. The only way to learn what the Default filter is is to copy it so you have edit fields.