Branding icon doesn't work on Mac or Linux

[nedtwigg]

We set the icon like so

equo-ide/solstice/src/main/java/dev/equo/ide/IdeHookBranding.java

Lines 129 to 139 in 70ae380

	Image icon =
	loadImage(
	Display.getDefault(),
	IdeHookBranding.this.icon,
	"dev/equo/ide/equo_icon.png");
	Shell[] shells = display.getShells();
	for (var shell : shells) {
	shell.setText(title);
	shell.setImage(icon);
	shell.forceActive();
	}

but this means that we are not setting all the possible sizes (e.g. 512x512, 256x256, 128x128, 64x64, 48x48, 32x32, 16x16). Windows is happy with our current approach, but the icon doesn't show up on Mac or Linux. Autoscaling the provided icon to all these sizes and setting them all should fix it.