public static ResourceFile getInstallationDirectory() {
		checkAppInitialized();
		return app.layout.getApplicationInstallationDir();
	}
Returns the installation directory.  In an installation, there is only one application root
and its parent is the installation directory.  If not an installation, then this call doesn't
really make sense, but it will return the parent of the first installation root.
@return the directory
Ghidra/Framework/Generic/src/main/java/ghidra/framework/Application.java