Ask user for video generation at the end

[sassman]

Given

• a user runs t-rec normally, without the --video argument.

When

• t-rec is ending, just before t-rec terminates, it should ask the user interactively if they also would like a mp4 video of the recording. The question should have a default of [n]o (hit enter)

Then

• The video should be generated as if the user would have provided the --video argument