Conservative mode

[dandancheeseandham]

The point of this patch is to create file for all newly built units to have a default, safer config. I ran this myself when commissioning (perhaps it should be called "commissioning" mode instead , lol) and it was great. Gave me piece of mind and more reaction time during the inevitable head crashes (because my probe wasn't hooked up) :D

Currently has:

• Default heater models can be stored here
• Slower travel limits
• Probing with higher dive height (to prevent gouged beds, which is what I learnt) and set to a slow speed.

And can contain anything else you see fit for first run scenarios.

[lostapathy]

What's the logic between overriding M558 H10? Intuitively, a bigger value there seems less conservative in terms of machine safety but I'm probably missing something that we should try to document.

[dandancheeseandham]

More commented code