add MPGJog wheel example ..

[zarfld]

add MPG-Jog on pokeys based on https://linuxcnc.org/docs/stable/html/examples/mpg.html

problems to solve:

• using kbd48CNC the behaviour for selecting axis and scale seems different.

not sure if there is already a component which might help.

[zarfld]

for MPGjogging (also continuos Jogging and increment jogging) an extension was needed, as the pokeys component provides a bit for each button only, and linux cnc expects different behaviour (for mpg-jogging axis/joint pins are used for interaction, increment-jog needs halui.joint.?.increment-plus (/minus), continuous-jog uses halui.joint.?.plus(/minus); increment and continuous jog set jog-speed, mpg-jog uses jog-scale and jog-accel-fraction on axis/joint instead) this was packed in an additional kbd48CNC.comp which can be loaded if needed - signal/pin-mapping and component load was done in kbd48CNC.hal - to keep this part seperated from main config