Normalize a 48-bit MAC to colon, dash, compact, or Cisco-style groups.

• Colon A0:B1:C2:D3:E4:F5
• Dash A0-B1-C2-D3-E4-F5
• Compact A0B1C2D3E4F5
• Cisco A0B1.C2D3.E4F5