Upgrade Content API Client to 3.2

For some reason a bunch of arbitrary things have changed in version 3, like the name of the ApiError class and the package the client uses. Hence this massive pull request, sorry. :-1: 

CC @rich-nguyen @gklopper @phamann 

We need to upgrade because the latest version contains the fields by which we can sort the contributors in proper alphabetical (last name first) order.