Sandbox/Subsandbox

Subpage of sandbox. Was unable to create with VisualEditor. REST 404 when trying to hit the save page button, after the summary field

Editing pages with slashes in their name is ok after making this change https://phabricator.wikimedia.org/T270376#7365202 and this change to the Apache2.4 httpd configuration mw:Extension:VisualEditor#Allowing_VisualEditor_on_page_titles_containing_slashes