增加一个task，可以执行tasks.json内任意一个task

src/MaaCore/Task/Interface/CustomTask.cpp

@@ -0,0 +1,19 @@
+#include "CustomTask.h"
+#include "Task/ProcessTask.h"
+
+asst::CustomTask::CustomTask(const AsstCallback& callback, Assistant* inst) : InterfaceTask(callback, inst, TaskType)
+{
+
+}
+
+bool asst::CustomTask::set_params(const json::value& params)
+{
+    std::vector<std::string> tasks {};
+    for (const auto &i : params.at("task_names").as_array()) {
+        tasks.emplace_back(i.as_string());
+    }
+    auto custom_task_ptr = std::make_shared<ProcessTask>(m_callback, m_inst, TaskType);
+    custom_task_ptr->set_tasks(tasks);
+    m_subtasks.emplace_back(custom_task_ptr);
+    return true;
+}