Support locale at StartConversation

[timenick]

##Issue
Original issue: microsoft/botframework-obi#75

This issue tracks a frequently requested feature to allow a user locale when starting new conversations. The user locale is needed so that bots can send a properly localized Greeting Message to users.

##Proposed change
WebChat - update the protocol to support locale and userId aligned with DirectLineJS

Tracking DirectLineJS issue: microsoft/BotFramework-DirectLineJS#292

[compulim]

Thanks @timenick. We will implement the startConversation.locale options.

Work items

Adding locale option

Update createDirectLine to accept and pass locale option.

  const directLine = window.WebChat.createDirectLine({
+   locale: 'en-US',
    token
  });

Add a sample to show how it works

We need a bot to show the greetings. Please update the MockBot2. Expecting:

1. When the user join the conversation, currently, it will say "Hello and welcome!"
   • Please update it with zh-Hans and say another message
   • You may need to bump Bot Builder SDK
   • This bot has CI/CD, will do automatic deployment via GitHub Actions
2. Test the bot at https://compulim.github.io/webchat-loader/, click "MockBot 2 (Preview)"

Add tests

1. Clone /__tests__/html/simple.html and simple.js
2. Add tests
   • (We always use visual regression test, you can look at the code, and run it under Docker to get the screenshots)
   • Test "no locale is sent", should return "Hello and welcome!"
   • Test "send en-US", should return "Hello and welcome!"
   • Test "send zh-Hans", should return the message in Simplified Chinese
   • Test "send xx-YY" (non-existing), should return "Hello and welcome!"
   • Test "send 1a2b3c" (non-ISO format), should return "Hello and welcome!"

To run tests locally

1. npm start
2. Navigate to http://localhost:5001/ and click on the test
3. Open F12 to see the test result
   • This route don't capture the screenshot although it said it is

To run tests in Docker

You must capture screenshots in Docker for cross-platform compatibility.

1. Install Docker
   • On Windows, we currently run on WSL1 but not WSL2 yet
2. Run docker-compose up --build to start the Selenium Grid
3. Run npm test (or npm test -- --testPathPattern __tests__/html/simple to scope down)
   • When the new tests are run, the screenshot will be saved to disk automatically