doxygen: add page (#1812)

pages/common/doxygen.md

@@ -0,0 +1,15 @@
+# doxygen
+
+> A documentation system for various programming languages.
+
+- Generate a default template configuration file "Doxyfile":
+
+`doxygen -g`
+
+- Generate a template configuration file:
+
+`doxygen -g {{path/to/config_file}}`
+
+- Generate documentation using an existing configuration file:
+
+`doxygen {{path/to/config_file}}`