add firefox extension template

externs/webextension_polyfill/pkcs11/Static.hx

@@ -0,0 +1,20 @@
+package webextension_polyfill.pkcs11;
+
+typedef Static = {
+	/**
+		checks whether a PKCS#11 module, given by name, is installed
+	**/
+	function isModuleInstalled(name:String):js.lib.Promise<Bool>;
+	/**
+		Install a PKCS#11 module with a given name
+	**/
+	function installModule(name:String, ?flags:Float):js.lib.Promise<ts.Undefined>;
+	/**
+		Remove an installed PKCS#11 module from firefox
+	**/
+	function uninstallModule(name:String):js.lib.Promise<ts.Undefined>;
+	/**
+		Enumerate a module's slots, each with their name and whether a token is present
+	**/
+	function getModuleSlots(name:String):js.lib.Promise<Null<Any>>;
+};