Allow setting up replay server by clicking on match times

The idea by etigah is that match times (i.e. `[15:34]`) should be clickable on the web page and it'll communicate to the respective replay server (see #3) and set up the replay to start playing at that time, minus a few seconds, so a player can join and start watching at that exact time.

There are two approaches that this could take:

1. Have a bzadmin client join the replay server and configure things for people
2. Expand/use the bzfs plug-in API to
- accepting incoming HTTP requests
- load the replay file and skip time

Depends on #3