Show how many songs are in a album in the information panel

Versions:
VLC: 22th August 2021 nightly build
-OS: Windows 10.0.19043.1165

changed milestone to %Qt redesign (VLC 4.0)

added Component::Interface: Qt label

added Type::feature label

We have to discuss if we want to have that given we already have the track listing.

assigned to @bunjee

If there are many like 15+ then going through and count how many tracks there are is kind of difficult and annoying in my opinion

mentioned in merge request !829 (merged)

closed with merge request !829 (merged)

closed with commit 32c618fa

changed milestone to %4.0