Partial fix for issue #1274, converting exec() to Process()

[mrducky4]

I tested in the development VM. I tested the translators change from the Translation Center page, as an admin, deleted the locale is_IS and verified the files and directories were actually deleted. I tested the clean uploads trash job with run_background_job.php CleanUploadsTrash and verified it deletes TRASH/... files older than 30 days and deletes empty folders.

Update by cpeel: Sandbox avail at https://www.pgdp.org/~cpeel/c.branch/process_class/

[mrducky4]

Thanks for the comments. I can make the minor updates to address the feedback.