Add menu item types for Proofing galleries

[postmastersteve]

Users must create manual links to their Proofing pages and galleries. ProPhoto 5 provided some special menu items when Proofing was installed. Consider adding these to ProPhoto 6:

• Recent proofing galleries dropdown
• Proofing gallery archive page (the main gallery slug)
• Proofing gallery category page (individual)
• Proofing gallery categories dropdown
• Select proofing gallery (individual gallery)

Since these overlap with existing menu item types, we might achieve this by adding a toggle or option in the existing menu item types when Proofing is running. Or, we could create new menu link types.

[postmastersteve]

+1 Andy Woo ticket 170740