Add services and keys module to the account settings page

[saleiva]

No description provided.

[javisantana]

this requires a change in user model, adding a key and some controler change to get it. We will do without backend help cc @Kartones @rafatower @juanignaciosl

[Kartones]

Most backend changes are already implemented:
https://github.com/CartoDB/cartodb/blob/master/app/controllers/api/json/imports_controller.rb#L231
https://github.com/CartoDB/cartodb/blob/master/app/controllers/api/json/imports_controller.rb#L112

It would only need a new endpoint to list all services of a given user.

[xavijam]

Ok! Sounds super good!