Camera selector help

[TheMariday]

As a user
I want to know if there are multiple cameras detected
so that I can choose the right one.

current idea:

• rename --device to --camera
• if --camera hasn't been provided, then check to see how many devices are connects
• if it's 1, then use that, if it's more than 1, list the camera device id's, throw a warning asking the user to select which camera they want to use with --camera and quit

I could do some CLI stuff but I would prefer all settings to be captured in args so that minimal thought is required for the actual operation. i.e. you don't want to have to select the camera every time and if you forget then it will warn you.

note: might be good to add in the docs that you need to use the same camera for the entire reconstruction