Firmware Updates - E step value resetting, and enclosure lighting

[xchrisd]

I did a request about tool-change:

Discussion of Snapmaker 2.0 Firmware Updates

Firmware and Touchscreen Request: Tool change mode to easily change the toolhead. Need the enclosure light on and the tool head in service position, no machine-failure when unplugging the tool-head. @JKC20 @Edwin