DFN: Update pin 1 silk style

Update manually-drawn DFN silkscreen for v8 (part of #2637).

Contains the following changes:

• Use the new arrow-style silkscreen:
  • Arrow at pin 1 corner, pointing down and right
  • Lines at the top and bottom
• Normalised fab and silk line thicknesses: many parts used 0.15mm for both.
• Normalised a few chamfers to max 25%
• Normalised fab refdes sizes (many had sizes under 0.5mm or odd thicknesses) and rotations
  • One had the red des moved outside as it couldn't fit a one-letter-two-digit refdes in the body at 0.5mm size
• Added 0.2mm silk clearance where it didn't exist before
• Update 3D model paths

Includes all (I think) non-generated parts in PackagE_DFN_QFN and 2 parts in OptoDevice that haven't been updated yet.

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Example (one of many):

KLC violations - all pre-existing as far as I know

• EC02: Some pads not rounded
• F6.3: Paste pads trip up the layer check
• F9.2: Some parts have mask clearances set
• F9.3: Some 3D model names don't match the footprints, but the models exist at the current paths