Accessibility: use Table instead of ARIA Grid

[henrikaskj]

The table in the ClientFS perspective is an ARIA Grid. I think it would improve accessibility if it was a Table element like in the other perspectives.

[henrikaskj]

Never mind, it seems the react-virtualized developers have done a thorough job on addressing accessibility issues:
bvaughn/react-virtualized#1624
Spamming ARIA often does more harm than good for screen reader users though, so it could be an idea to replace react-virtualized in the future