Add new directory structure for page objects

Creates new directory structure for page objects that reflects horizon main
menu. Pageobjects should be located in the directories according to their
location in the main menu.

Partially implements blueprint: selenium-integration-testing
Closes-Bug: #1348232

Change-Id: Ibed2581721be114d696673038d1381a6002aef58
Merge "Add new directory structure for page objects"