Update Resources/Private/Templates/Page/WithSidebar.html

Added <flux:flexform.field.checkbox name="addWell" label="Add 'Well' to Sidebar" />
Because there is an if statement inside the PageObjects.html but no flexform.field anywhere.		
Merge pull request #1 from grimmcreative/patch-1

[FEATURE] Update Resources/Private/Templates/Page/WithSidebar.html