Add List Campaigns for Advertiser to the JS and Ruby Management SDKs

[amandamc]

This popped up from a support ticket brought to @clairehansen for GoDaddy. They were trying to use the JS Management SDK to list campaigns per advertiser and it was not working. Upon further inspection of the SDKs, I found that neither the Ruby or JS SDKs implemented the ability to list campaigns per advertiser like our documentation says.
Here is the documentation: https://dev.kevel.co/reference/list-campaigns