Add 'M114 E' to get E stepper position (M114_DETAIL)

[bigtreetech]

Description

• Add command to get the pulse count of extruder in real time

Benefits

• When using touch screen for printing, the touch screen can get the actual position of the extruder in real time, and then detect the encoder filament sensor to determine whether the filament is extruded normally

[thinkyhead]

To keep the default build from growing larger this PR has been slightly changed:

• M114_DETAIL must be enabled to be able to use M114 E.

[thinkyhead]

When using touch screen for printing, the touch screen can get the actual position of the extruder in real time

• Note that it is common for slicers to reset E to zero on each layer, and perhaps even more often. So the E axis "position" tends to be a meaningless anchor for relative motion.
• For an example of accumulating total E movement (in mm), see the LCD_SHOW_E_TOTAL feature.
• Note that you must obtain the M92 E value to be able to convert stepper steps to mm.