New functionality to post a job with pdf file or entering url

The uploaded pdf file will be shown in an iframe on the job details page - this can help the company if they already have all the job information well formatted in a pdf file, to avoid entering the whole information again and keep everything well formatted with the company's logo and details.
We also added the option instead of submitting a pdf file, to enter the url of the job details, which is again shown in a frame and can be a file like pdf or simple web page showing the full job information.