feat: rework some designs and icons

[maotovisk]

As a inheritance from the old times where we used Material.Avalonia (even before SukiUI), we had Material.Icons.Avalonia as our icon provider. It was good but i felt it was a little bit outdated. We are now using Lucide.Avalonia which is a bit more modern and some SVGs from SimpleIcons for branded stuff.

In addition to that:

• a new smooth scroll implementation is being used, now trackpads should be respected.
• new font rendering parameters (hopefully should make it look lest clunky on linux)
• interactions on buttons don't freeze the UI thread anymore (map picker/from osu are expensive, moved into another thread)
• Better osu!lazer support on "from osu!", now it shows mount folder instructions.

Redesigns

The new designs implemented:

Start

Settings was tweaked