Setup defaults settings page and restructured forms class

- Added settings base class
- Set all form fields to be semi-independent of the meta helper, still needs some cleanup
- Added multiple form helper classes to make form fields more DRY
Added PHPDocs to settings class properties
Set correct @since PHPDoc values
Added settings page to Apperance instead of settings
Added helper method to retrieve individual setting
Added theme name to options page
Added options property to mdg_setttings
Merge branch 'feature/settings-page' into development
Fixed meta fields outputting to every page
Added after title meta
Removed a few old unused plugins from composer and required plugins