Add in a pref for camera orbit speed multiplier

[GCRev]

Description

The amount of rotation during camera orbit always struck me as too high, and I've wanted to be able to reduce it for quite a while. I suppose that this could be part of the character of slic3r, but I think it is sensible to add a pref for anyone who would like to adjust it.

I've placed this pref with the other camera prefs. It does some basic validation and formatting on the input value to keep it at two decimal places, and between a min and max of 0.05 and 2.0 respectively. This should be more than enough of a range and precision.

It defaults to 1.0 so that there is no change in the existing behavior.

I thought I might also mention that the reason I added an entirely new component for this pref is because there was no existing component that would perform the tasks required all at once which are:

• accept a float-valued numeric input
• perform custom validation on the input to limit to a min and max
• format the output to limit the decimal precision to something reasonable
• only update the saved value in the config once validation passes, and without saving twice

Screenshots/Recordings/Graphs

Tests

I've manually verified the behavior and checked that the pref is stored into OrcaSlicer.conf for recall.