pangolin: add page (#15346)

pages/common/pangolin.md

@@ -0,0 +1,12 @@
+# pangolin
+
+> Implements the dynamic nomenclature of SARS-CoV-2 lineages (Pango nomenclature).
+> More information: <https://cov-lineages.org/resources/pangolin/usage.html>.
+
+- Run `pangolin` on the specified FASTA file:
+
+`pangolin {{path/to/file.fa}}`
+
+- Use the specified analysis engine:
+
+`pangolin --analysis-mode {{accurate|fast|pangolearn|usher}}`