Allow users to update their email address (#1745)

* Change email address

* Email confirmation

* Email change test

* Lint

* Schema reset

* Set test email sender

* Select specific user fixture

* Refactor/cleanup

* Remove unused email_confirmation_token

* Current user would never be true

* Fix translation test failures

app/controllers/email_confirmations_controller.rb

@@ -0,0 +1,18 @@
+class EmailConfirmationsController < ApplicationController
+  skip_before_action :set_request_details, only: :new
+  skip_authentication only: :new
+
+  def new
+    # Returns nil if the token is invalid OR expired
+    @user = User.find_by_token_for(:email_confirmation, params[:token])
+
+    if @user&.unconfirmed_email && @user&.update(
+      email: @user.unconfirmed_email,
+      unconfirmed_email: nil
+    )
+      redirect_to new_session_path, notice: t(".success_login")
+    else
+      redirect_to root_path, alert: t(".invalid_token")
+    end
+  end
+end