Define software limits for config settings

[kyle-kingsbury]

Currently, you can set configs freely. I do not know the extent of it yet but I was able to set my maximum feed rate to 2000 IPS and adjust my maximum jerk to accommodate that with no warnings or anything. This creates a situation where people can really screw up their config cognitively, or by accident. The fact that these settings can be changed while the machine is running makes this even more of an issue.

[RobMackie]

put limits on the inputs in the config screens.