Revise description of the overall runtime for the tutorial to reflect "hands on" time vs. run time

[huddlej]

Current Behavior

The current tutorial states that users can learn how to setup their own custom Nextstrain build in an hour, but the actual run-time of the tutorial is much longer right now.

Possible solution

Update tutorial content to describe the amount of time users should expect to spend in terms of "hands on" time and "analysis" time. The first category accounts for how much time users spend at their computer while the second category accounts for how long the actual workflow may take to run on a standard personal computer.

Additional context

This issue was originally raised by Stacia Wyman on the Nextstrain discussion board.