Refactored maintenance module to use fluent
Fixed function call
Fixed a non static reference

Just something I found while hacking around 2.3.
Merge pull request #2531 from wshatch/patch-2

Fixed a non static reference
Merge remote-tracking branch 'upstream/2.3/develop' into feature/maintenance
DB doesn't exist yet, lets do it the ugly way
Merge pull request #2523 from swilla/feature/maintenance

Eloquent Refactor of Maintenance Module
Moved the Maintenance export logic back into a "Data" model.
Ran PHP CS Fixer with the following:
    php-cs-fixer fix ./installer --fixers=trailing_spaces,unused_use,php_closing_tag,short_tag,return,visibility,braces,phpdoc_params,eof_ending,extra_empty_lines,include,controls_spaces,elseif
This will ignore the requirement for class names to match the filename as for now CodeIgniter has lowercase files for controllers and upper-case class names. We'll do it this way for now as we move as much coder over to being a composer package as possible.
merge back from upstream