Add support for the 2020 Homeless Management Information System (HUD HMIS) Data Standard Questions from HSLynk

Currently, the app supports up to the HMIS 2017 Data Standard, but communities need the new 2020 standard questions.

The HUD HMIS 2020 Data Standard is at: https://www.hudexchange.info/resource/3824/hmis-data-dictionary/

The HSLynk Open Source 2020 HMIS Platform APIs are here: https://docs.hslynk.com/?urls.primaryName=HMIS%20vFY2020%20API%2C%202020%20API 

cc: @CTAJavier