fix all of phpstans errors

[workaj]

what the title says

notes:

• disables checks for lines referencing Config::$caching, this should be addressed long term

[workaj]

4 more errors to go, these ones will require some digging in to not break things:

 ------ ------------------------------------ 
  Line   core/content.php                    
 ------ ------------------------------------ 
  :514   Undefined variable: $custom_fields  
  :540   Undefined variable: $new_content    
 ------ ------------------------------------ 

 ------ ---------------------------------------- 
  Line   core/content_search.php                 
 ------ ---------------------------------------- 
  :95    Undefined variable: $custom_field_name  
  :114   Undefined variable: $custom_field_name  
 ------ ---------------------------------------- 

[workaj]

note this just level 0 checking, probably eventually want to get to level 4 sooner rather than later. level 9 is moonshot