Remove session controller actions other than delete

and do some general cleanup around sessions controllers and the
sign_in_as test helper

app/controllers/sessions_controller.rb

@@ -1,28 +1,6 @@
 class SessionsController < ApplicationController
-  require_unauthenticated_access only: %i[ new create ]
-  rate_limit to: 10, within: 3.minutes, only: :create, with: -> { redirect_to new_session_path, alert: "Try again later." }
-
-  before_action :require_first_run_completion
-
-  def new
-  end
-
-  def create
-    if user = User.active.authenticate_by(params.permit(:email_address, :password))
-      start_new_session_for user
-      redirect_to after_authentication_url
-    else
-      redirect_to new_session_path, alert: "Try another email address or password."
-    end
-  end
-
   def destroy
     terminate_session
-    redirect_to new_session_path
+    redirect_to Launchpad.login_url, allow_other_host: true
   end
-
-  private
-    def require_first_run_completion
-      redirect_to first_run_path if Account.none?
-    end
 end