sets up web templates to have parents for building nested navigation
adds migration file for parent_id
Add attributes to navigation setting
Add top_level and child_templates to has_setting_navigation
Add specs for navigation concern
Add child_template? method
updates nav settings when a parent_id changes,
changes some space formatting
changes whitespace
Use dropdown select for parent page admin
gets parent dropdown working with bindings etc.
changes method name to children, seems more concise
changes spec to reflect changed method name
 changes definition of top-level web template
fetches only top_level pages for navigation settings,
sets up child pages in similar fashion to top levels as a hash with id`s as keys
fixes specs to reference new children structure,
and work with narrower scope of enabled only pages
sets up a property for the web_page_template select box,
to not show the template whos setting you are working with
Merge pull request #410 from G5/nested-navigation-72359444

Nested Navigation 72359444
Merge branch 'master' into bundle-update-74863314
be_true is now be_truthy