This commit introduces the possibility to stream messages. To allow plugins to use streaming this commit also ships a `ChatSDK` library to allow to interact with few parts of discourse chat.
```ruby
ChatSDK::Message.create_with_stream(raw: "test") do |helper|
5.times do |i|
is_streaming = helper.stream(raw: "more #{i}")
next if !is_streaming
sleep 2
end
end
```
This commit also introduces all the frontend parts:
- messages can now be marked as streaming
- when streaming their content will be updated when a new content is appended
- a special UI will be showing (a blinking indicator)
- a cancel button allows the user to stop the streaming, when cancelled `helper.stream(...)` will return `false`, and the plugin can decide exit early
