Only load it once the first chat has been opened.

This will make it easier to add config-based functionality, such as
allowing/showing the `/topic` slash command only to those users who are
allowed to set the subject.

The .chat-content are doesn't resize when the textarea gets resized to
its original size once a message gets sent.

- Use flexbox where possible
- Simplify header by using `justify-content` instead of setting column widths
- Show description below the row containing the title and buttons

and use some native ones instead

and bump post-release version number