Display the currently installed version of a feature in the update wizard

[pcdavid]

When running an update, the UI only shows me the new/future version of the elements to update:

It would be nice to have both "Current version" and "New version" to be able to decide if I want to select an update or not (e.g. it a minor/service release compared to what I already use?)

[laeubi]

@pcdavid do you like to propose a PR?

[pcdavid]

@pcdavid do you like to propose a PR?

I had a quick look at the code to see if it was something that was relatively trivial, but it doesn't seem like it. I'm not familiar at all with the p2 code base and do not have time available to dig further, sorry.