add tasker module description and samples

samples/tasker-test.lua

@@ -0,0 +1,19 @@
+local tasks = {}
+
+function on_resume()
+    tasks = tasker:get_tasks()
+    ui:show_lines(tasks)
+end
+
+function on_click(idx)
+    tasker:run_task(tasks[idx])
+end
+
+-- Optional
+function on_task_result(success)
+    if success then
+        ui:show_toast("Successfull!")
+    else
+        ui:show_toast("Failed!")
+    end
+end