A common complaint is that --frames-per-lambda is cumbersome to use

• One does not know the duration of the video yet when invoking the command
• You just want to have a specific concurrency like 100

Goals:

• Support this new flag in renderMediaOnLambda() and npx remotion lambda render
• Should ignore if this would mean a framesPerLambda < 4
• If both framesPerLambda and concurrency are set, then throw
• Document it