Refactor `StatusBarHoverManager` for general use

[colin-grant-work]

Suggestion: I believe that this StatusBarHoverManager can actually be used as a general HoverManager, if we change the requestHover method to accept an options element. Something like in vscode where we can set the position (above, below, left, right) of the hover.

This could supersede the existing hovering support for the vsx-registry view for example.

Originally posted by @msujew in #11083 (comment)

[colin-grant-work]

I believe that this was implemented.