Implement lag delay and extend replay length durations to 12 seconds.

[Bernie]

This adds a parameter to delay the replay recording by the given duration in seconds. This differs from the delay parameter provided in the replace kiosk in that it actually delays the recording start instead of simply delaying the replay.

This was implemented as we found the "live recording" from the replay kiosk was often a few seconds behind, and in some extreme cases would completely miss the replay by ending before the race actually started in the replay stream.

Fine tuning this parameter helped us to reliably capture the race.

This PR also extends the replay duration options as we found a longer duration would help in ensuring we captured the race.

[jeffpiazza]

I've finally read this through well enough to understand it, and I'm mostly OK with adding this.

I think I'd prefer to adopt recording_delay over lag as the name of the variable and element. Happily that matches the explanatory text on the input.

Correspondingly, the current "delay" input and variable should probably be renamed playback_delay for symmetry.

If you can make those changes, I'd be happy to merge this in.