Add smart bed leveling

[julie777]

Is your feature request related to a problem? Please describe.

Most of the time I do not want to repeat bed leveling so I turn it off. However there are known times when the bed should be leveled before starting a print. I would like to see this automated.

Describe the solution you'd like

I am not sure how much of this can be done in just the slicer, but in combination with the firmware it is not a complicated feature.

1. Identify all the times when the bed should be leveled before printing.
2. If any of the conditions are true then automatically add bed leveling to the start of the print.

Conditions that I know of that (probably) require the printer to run the bed level calibration.

1. After a failed print - any print that is stopped before completion
2. after the printer has been power cycled. This is based on my belief that the printer does not save bed calibration across power cycles
3. after a firmware update
4. when the plate type is different from the previous print

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.

[JonK111]

Why not do a hybrid? I love how Prusa does bed leveling just around the part that will be printed....
Example: Say the part I want to print is 3.5 inches x 4.5 inches. The printer should be smart enough to level only an area maybe about 4 inches x 5 inches. This would significantly reduce the number of points tested for bed leveling with the same end result. No need to level the whole bed if I am not printing on the whole bed.