Investigate usage of SVG images instead of PNG

**What is the current behaviour and why should it be changed?**

Currently we mainly use png images (even in places where vector based images would be beneficial) . We should discuss if we want to move to SVG instead. This has the advantage of a potentially smaller app, easier size modification. However it's more complex to render them.

**Describe possible approaches**

Convert new images to SVG. This might introduce a new Qt dependency.

@jamulussoftware/designers I assume you're already working on the new instrument set in SVG format?

**Has this feature been discussed and generally agreed?**

No. However see: https://github.com/jamulussoftware/jamulus/pull/2508

Inizia esaminando l’uso attuale delle immagini PNG in Jamulus e la pull request correlata #2508. Verifica se il rendering di SVG richiederebbe una dipendenza da Qt e documenta un approccio concordato per convertire le nuove immagini o adottare SVG in modo più ampio.

Scritto dal modello di indicizzazione a partire dal testo della issue.