Allow additional civic entities

[jqnatividad]

Would be awesome if athena-civic can be extended to show relationships between other entity types, specifically, stuff that we'll be scraping out of City Record, e.g.:

• procurement contract info (e.g. contractor, project, contract, etc.)
• geotemporal info (e.g. places in NYC, events, etc. - this would make an interesting viz beyond your typical graph viz if the geotemporal stuff is being visualized)

see https://talk.beta.nyc/t/closed-poll-best-civic-hack-best-of-show/442/2