Add "Acknowledge" section to About page

[jwhaney]

"Users can view the page to see which entities, and how these entities, have contributed or provided feedback that is used to improve the site. This section should be located below the Data Sources Section."

[jwhaney]

@LaurenKirk @csidenblad, do we know what this information is now? or should this wait/move to tier 3?

[LaurenKirk]

@jwhaney please move to tier 3. I imagine we will collect this data towards the end