Use SH for RJ45 shield pins

Parts Abracon ARJP11A-MA and Amphenol RJMG1BD3B8K1ANR used numerical shield pins. Change to SH (KLC 3.7).

Also tweak other magjack graphics.

• https://abracon.com/Magnetics/lan/ARJP11A.PDF
• https://www.amphenol-cs.com/media/wysiwyg/files/drawing/rjmg1bd3b8k1anr.pdf

Graphic tweaks:

• Harmonise connection dot size, component sizes and shapes
• Use slightly thicker lines to mark out components vs wires
• Correct placement of coil polarities
• Rotate RJ45 graphic to match wire layout

Old graphics:

New graphics:

Footprint MR: kicad-footprints!3181 (merged)

Relates to the todo here: #3002

KLC voiolations:

Abracon part: S4.5: pin 8 missing. The part doesn't have a pin 8.

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