Fix import & use of SchemaUtility to StreamSchema

Issue https://github.com/pyrocms/pyrocms/issues/3190
2.3/Dev Fix mkdir() installation error
Fix 'hidden' field error
Fix StreamSchema on pages
Fix is_unique & is_locked on install
Fix StreamSchema on users
Fix StreamSchema on variables
Add sorting by BelongsTo relations
Improved order by logic
Merge pull request #3192 from jasonagnew/2.3/develop

2.3/Dev Fix for Install Errors (SchemaUtility, mkdir()  & hidden field)
Stop bitchin dang generator
Removing left over code used for testing
Added ability to save each model from the collection
Lets see if this fixes the inconsistency between the installer controller and MY_controller
Update pyrocms required key on theme options
Add ability to pass field data values in closures
Update blog install