Show more meaningful error when CUPS-BSD is not installed

[tresf]

On some systems (such as Raspberry Pi OS) the package CUPS-BSD is needed for Java to print. We should consider showing a more meaningful error when CUPS-BSD is not installed.

See also:

• Getting java.awt.print.PrinterIOException on RP5 and CUPS #1341

Currently at install time, we ask the user to install certutil, we may decide to do the same for cups-bsd.

tray/src/qz/installer/certificate/LinuxCertificateInstaller.java

Lines 70 to 75 in 5e01218

	public void setInstallType(Installer.PrivilegeLevel certType) {
	this.certType = certType;
	if (this.certType == SYSTEM) {
	log.warn("Command \"certutil\" (required for certain browsers) needs to run as USER. We'll try again on launch.");
	}
	}