Add a date last run column and allow columns to be sortable

[andykearney]

As the title says really. We manage all our products via google sheet feeds. 27,000+ variants. There's often updates once the initial import has been run, price changes etc. Having a time stamp for the last time a feed was run would be very helpful.

Also, allowing columns to be sortable would be helpful too. Organise alphabetically etc. We're currently at 122 feeds and counting and a little more organisation would save a few life minutes.