Resolve "Consider using the `genpdf` crate for generating PDF documents from analysis reports."

Closes #73 (closed)

examples/report_generator.rs

+use std::path::Path;
+
 use chrono::DateTime;
 use opossum::{
     error::OpmResult,
     properties::Properties,
-    reporter::{AnalysisReport, DetectorReport, ReportGenerator},
+    reporter::{AnalysisReport, NodeReport, ReportGenerator},
+    spectrum::create_he_ne_spectrum,
 };
 
 fn main() -> OpmResult<()> {
@@ -15,9 +18,12 @@ fn main() -> OpmResult<()> {
         .create("total energy", "energy of detector", None, 1.012345.into())
         .unwrap();
     props.create("my bool", "", None, true.into()).unwrap();
-    let detector = DetectorReport::new("powermeter".into(), "my powermeter".into(), props);
+    props
+        .create("spectrum", "", None, create_he_ne_spectrum(1.0).into())
+        .unwrap();
+    let detector = NodeReport::new("powermeter".into(), "my powermeter".into(), props);
     report.add_detector(detector);
     let generator = ReportGenerator::new(report);
-    generator.generate_pdf();
+    generator.generate_pdf(Path::new("./playground/output.pdf"));
     Ok(())
 }