Use configured custom hover delay for views

[bpasero]

As a heavy user of the mouse for reaching to activity bar and views, I find the current hover feedback to much into my face.

This is especially bad because the hover is on top of the view that is current, so it might hide some important information that is below.

I suggest to:

• use the workbench configured hover delay
• make the color themeable so that it can be turned off if wanted

PS: should probably not be a hover in panels:

[bpasero]

Btw why are we actually using a custom hover when the native one already works?

[sandy081]

Reopened the main issue - #118077 to continue discussion there as it has more context. Please comment there.