Add missing event name translations

We were always displaying the event names in English.

Note we're changing the `user_supported_budgets` key because it didn't
make much sense; the investments are supported, and not the budgets.

We're also adding "created" to most of the event names in order to make
the texts more explicit, since not all the events refer to created data.

spec/controllers/admin/api/stats_controller_spec.rb

@@ -29,7 +29,7 @@ describe Admin::Api::StatsController, :admin do
         get :show, params: { event: "proposal_created" }
 
         expect(response).to be_ok
-        expect(response.parsed_body).to eq "x" => ["2015-01-01", "2015-01-02"], "Citizen proposals" => [2, 1]
+        expect(response.parsed_body).to eq "x" => ["2015-01-01", "2015-01-02"], "Citizen proposals created" => [2, 1]
       end
     end
   end