proposal: 使用工具自动测试 Quickstart 文档

[seeflood]

Quickstart 是项目的门面, 如果新用户进入仓库后，发现 Quickstart 文档跑不起来，可能会失望的走掉。

所以我们要经常性的测试 Quickstart, 保证能正常运行。

但是……定期手动测试 Quickstart、修复文档中的异常，这个过程实在太花时间了：

烦死了！

我们用工具自动测试文档吧！

提案：

1. 编写 Quickstart 时，需要按照规范，保证运行文档不会报错
2. 用工具自动测试文档
3. 以后把文档测试加入 CI 里

详细说明见 https://mosn.io/layotto/#/zh/development/test-quickstart

[seeflood]

We can split this issue into different tasks:

• refactor quickstart document for State API and make it testable. See ci: check dead link and test quickstart #451
• refactor quickstart document for pubsub API and make it testable.
• refactor quickstart document for Configuration API and make it testable.
• refactor quickstart document for Lock API and make it testable.
• refactor quickstart document for Sequencer API and make it testable.
• refactor quickstart document for RPC API and make it testable.
• refactor quickstart document for File API and make it testable.
• refactor quickstart document for API plugin and make it testable.
• refactor quickstart document for Layotto Actuator and make it testable.
• refactor quickstart document for Skywalking and make it testable.

The state API document is ready for test and can be taken as an example.