You could use a scheduled process trigger to periodically call a JSS script that iterates through a folder-tree deleting any files that are older than 14 days.
Something like the following should do the trick:

Here's the script so that you can copy-and paste:
var maxAgeInDays = 14;
var baseFolder = "/Home";
// Deletes all files in the given folder (and all its sub-folders)
// that are older than maxAgeDays
function deleteOldFiles(folder) {
folder.getFiles().forEach(function(f) {
if (f.isFolder())
deleteOldFiles(f);
else {
var now = new Date();
var msPerDay = 1000*60*60*24;
var ageInDays = (now.getTime() - f.modifiedTime.getTime()) / msPerDay;
if (ageInDays > maxAgeInDays)
f.removeFile();
}
}
}
// Call removeOldFiles on the base folder
deleteOldFiles(system.getFile(baseFolder));