Formatted workspace intro, custom "Commit" background and more

Today we added the possibility to change the background color for the "Commit" theme. You may now use a color that fits your brand a little more.

We also added a couple of formatting options for the workspace intro. This allows you to set bold, italic, lists and links to the intro of your workspaces. In a future update, we may add some additional options.

Apart from that, we also fixed a few bugs and made some minor improvements to the themes.