Rename Amphenol RJ12 54601 to 54601-x06_Horizontal

Rename RJ12_Amphenol_54601 to RJ12_Amphenol_54601-x06_Horizontal since there are in fact other kinds of 54601 socket out there (like the 54601-x08).

Resolves #2522 (closed).

Also some minor tweaks:

• Remove silk where a board edge could be
• Fab ref des orientation
• Cut in courtyard to 0.5mm where possible
• Move silk outside body outline, remove some tiny silk fragments
• Rounded pin 1
• Move pins to the left by 0.01mm (!) to match DS
• Add some description