List documents on the screen

[hackerwins]

What this PR does / why we need it?

I implemented ListDocuments API one of the Admin APIs to Yorkie in yorkie-team/yorkie#309.
In this PR, we call ListDocuments to display a list of documents on the screen.

• List documents on the screen.
• Remove counter and add documents feature
• Leave counter feature for reference

Any background context you want to provide?

You need backend servers like Yorkie and Envoy to run Yorkie House. You can simply run them using docker-compose in your project root.

$ docker-compose -f docker/docker-compose.yml up --build -d

And you can create test documents using yorkie-js-sdk. To create them, start co-editing example in your yorkie-js-sdk.

$ npm start
$ open HTTP://0.0.0.0:9000/

What are the relevant tickets?

Address yorkie-team/yorkie#273

Checklist

• Added relevant tests or not required
• Didn't break anything