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, NodeReport, ReportGenerator},
+    spectrum::create_he_ne_spectrum,
+};
+
+fn main() -> OpmResult<()> {
+    let mut report = AnalysisReport::new("abc123".into(), DateTime::default());
+    let mut props = Properties::default();
+    props
+        .create("name", "blah", None, "my name".into())
+        .unwrap();
+    props
+        .create("total energy", "energy of detector", None, 1.012345.into())
+        .unwrap();
+    props.create("my bool", "", None, true.into()).unwrap();
+    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(Path::new("./playground/output.pdf"))?;
+    Ok(())
+}