Feature Request: Per-Resource Ramp-Up & Ramp-Down Duration

[LarsKemmann]

This would help immensely with modeling two key factors:

1. onboarding, which otherwise is very laborious to calculate across multiple variations of resources since each combination of resources requires updating the resource assignment for the onboarding activity, and
2. the cost of resources actually needing to stay on the project longer than their assigned work to provide what I'll term "cost slack" (for those projects where resource costs are a factor, this is absolutely critical -- it's one thing to say a task chain has a lot of slack, it's another thing to say we have team members allocated who can actually provide that slack!).