Add PHP memory limit into debug informaiton #6915
Description
I just submitted an issue about an out of memory problem, and went to the debug information for my Backdrop site on admin/reports/debug to paste into the issue, and noticed that memory limit wasn't included there. It is available on the status report.
I don't think we would have deliberately decided NOT to include memory limit, so I suspect this was just an oversight and could be added quickly. Adding 'good first issue` tag :)