Move published/draft/pending state out of 'permissions' (status)

Summary: move status selector to the main form, hide the form nav if theres only one section, fixes T934

Test Plan: try creating posts using forms that have one and more than one field, try creating posts with different statuses

Reviewers: rjmackay, vladimir, shadowhand

Reviewed By: shadowhand

Maniphest Tasks: T934

Differential Revision: https://phabricator.ushahidi.com/D447