Add custom management for data files through custom functions

this is what i've came up to for #696 

here is an example of the beginning of my customauth.php:

function getData($type, $file) {
    $project_data = $_SESSION["project_data"];
    $project_name = $project_data["project_name"];
    $project_path = $project_data["project_path"];
    $startup_file = $project_data["startup_file"];
    $replacements = array(
      "%PROJECTNAME%" => $project_name,
      "%PROJECTPATH%" => $project_path,
      "%STARTUPFILE%" => "$project_path/$startup_file"
    );
    $json = getJSON($file, "", false);
    $json = json_encode($json);
    $json = str_replace(array_keys($replacements), $replacements, $json);
    $json = json_decode($json, true);
    return $json;
  }
  function saveData($type, $file, $data) {
    return;
  }

you can store/retrieve data from anywhere to anywhere but for my case i'm still using the default behaviour
and now with this, i have nothing to whine about, everything works perfectly.