Dark theme for forums

[Kamdroid]

Fix and add the dark theme back to the forums.

My eyes will very much appreciate it.

[Hamed]

I think that the themes are working now. Give it a try.

[Kamdroid]

@hamed They are, thanks.

There are minor colour conflictions on certain elements.

In the Darkly theme the reply name is white text on a light grey background.

Also the post/reply writing window is still white.