[Feature Request] Add configurable warning for low-altitude flight

[jimmiedave]

Is your feature request related to a problem? Please describe.
My flight electronics (Eggtimer) don't arm for deploy below 200 feet AGL. Others probably have similar limits. Additionally, rockets of significant size require a certain amount of free-fall to get a properly-ejected chute open for a soft-enough landing.

Describe the solution you'd like
A configurable limit and fudge-factor for minimum altitude a sim achieves without a warning. Example: 200ft with a 100ft fudge factor (yes, this is 300 feet, but we could also offer altitude + fudge in percent of altitude). Fudge factor helps account for inaccurate sims and inaccurate altitude measurement by the electronics. If the sim apogee is below the limit, a strong alert. If the sim apogee is in the fudge factor range a "double-check this" alert.

Describe alternatives you've considered
Think it through myself, looking at all the sims. This works, of course, but doesn't automatically give me a heads-up to consider a potential problem or marginal condition.

Additional context
Default should probably be disengaged: setting up this limit and fudge factor should be an intentional act. Also, should be able to apply this across all currently-selected sims.