Add proper custom 404 page

src/site/pug/404.pug

@@ -0,0 +1,10 @@
+include includes/error
+
+doctype html
+html
+	head
+		title Not found | Bibliogram
+		include includes/head
+
+	body.error-page
+		+error(404, "Page not found.")

src/site/pug/friendlyerror.pug

@@ -2,8 +2,6 @@
 
 include includes/error.pug
 
-- const numberFormat = new Intl.NumberFormat().format
-
 doctype html
 html
 	head

src/site/server.js

@@ -19,7 +19,8 @@ subdirs("pug", async (err, dirs) => {
 	// need to check for and run db upgrades before anything starts using it
 	await require("../lib/utils/upgradedb")()
 
-	//pinski.addRoute("/", "pug/index.pug", "pug")
+	pinski.addRoute("/404", "pug/404.pug", "pug")
+	pinski.setNotFoundTarget("/404")
 	pinski.addRoute("/static/css/main.css", "sass/main.sass", "sass")
 	pinski.addPugDir("pug", dirs)
 	pinski.addAPIDir("html/static/js/templates/api")