VE-1663 Adding UI mapping to open the new gallery dialog
VE-1663 Adding functionalities of the dialog
Merge pull request #384 from Wikia/VE-1663

VE-1663: Create UI mapping for the new gallery dialog in VE
Adding test class
Merge remote-tracking branch 'origin/VE-gallery' into VE-1675

Conflicts:
	src/test/java/com/wikia/webdriver/PageObjectsFactory/PageObject/VisualEditor/VisualEditorMenu.java
	src/test/java/com/wikia/webdriver/TestCases/VisualEditor/VEGalleryTests.java