templates: Add a proper menu and navigation

internal/dis/component/menu.go

@@ -0,0 +1,36 @@
+package component
+
+import (
+	"html/template"
+	"net/http"
+)
+
+// Menuable is a component that provides a menu
+type Menuable interface {
+	Component
+
+	Menu(r *http.Request) []MenuItem
+}
+type MenuItem struct {
+	Title  string
+	Path   template.URL
+	Active bool
+
+	Priority MenuPriority // menu priority
+}
+
+func MenuItemSort(a, b MenuItem) bool {
+	return a.Priority < b.Priority
+}
+
+type MenuPriority int
+
+// Menu* indicates priorities of the menu
+const (
+	MenuHome MenuPriority = iota
+	MenuNews
+	MenuResolver
+	MenuUser
+	MenuAdmin
+	MenuAuth
+)