Add a column that notifies the last activity of device

[vongomben]

Last seen on <date/time> (possibly log device is the right place to look for it

[xrmx]

LogDevice would require some fixes, looking at it, i don't think it's doing what it's supposed to do.

UPDATE: it works, only in a strange way :)

[xrmx]

@vongomben since the api exposed to track device usage is not wired in the urls, should i make it available?

[vongomben]

yep.