Include Add Content menu

[michael-wynne-wsu]

Recreate the "Add Content" menu from v3.

This needs to include all relevant content types:

• Digital heritage item
• Collection
• Dictionary word
• Word List
• Person record
• Personal collection

Unsure at this time about site structure and users:

• Category (taxonomy)
• Community
• Protocol
• User

[michael-wynne-wsu]

@nick-deer (and @pjudge but I suspect out of scope for your current availability!)