Custom column sort order

[robinovitch61]

From @viniciusartus in #97

sorting by task state (dead, running), would be also useful.

[robinovitch61]

The complexity of this is not worth implementing for me given that

• there can be custom columns configured for each page, some of which may map to dynamic meta tags in jobs
• you can filter quickly for dead, running, etc. using the filter functionality on each page, or save the view and do a custom sort using something like awk