Replay caret

[refact0r]

I think this wouldn't be too hard to implement, just a caret that shows on the replay.

[unrealapex]

I think its a good idea, @lukew3 how achievable is this?

[lukew3]

Yeah, I like it too. I'm not familiar with how the cursor works right now and I'd like to finish backend migration first, so it might take a while for me to get to it.