Show tooltips on hovering over icons with no labels

There is a couple of places in the extension where we show icons for some operations, but don't show any explanation of what they do. Although the actions can be pretty easily understood from the context, I think it's still worth to add some labels or tooltips, just to make sure that the new users understand what's going on.

Problematic icons:

I think it would be the best to handle those icons similarly to how we handle the filter icon on the Portfolio abilities view (tooltip appears on hover).

Observed on 0.28.0