Group Contributors block role names change order

Because views uses role names in the categorization of blocks for organizers and contributors, we needed to originally change those role names accordingly. However, the cascading effect of this change was not optimal, IE 'Organizers' as a group name, being plural, doesn't make sense. Nor does adding a view label for 'member'.

Instead, we should create a view template for these associated blocks that grabs the role id and changes the label to show what we want, 'Organizers' and 'Contributors'

I've reverted the existing role changes, so you should just need to theme the view to get the labels looking correctly again. It looks like this in the interactive prototype:

https://projects.invisionapp.com/share/FW3OD3SQ#/screens/2438205