Change dashboard trends to only display last 3 years worth of data

[ajbarnes]

What is the expected state?
When I view the dashboard I want to see data that is no older than Jan 1 2020 in the trends panel.

What is the actual state?
When I view the dashboard I see data from the 1960s (possible corrupt VAs?)

Relevant context

• Consider tackling Change date used to report VAs #263 first as it will affect this issue.
• Question to consider: Should another issue be created to allow not keeping data older than X years in the first place? (ex. don't pull data older than 3 years from ODK and delete data in VA explorer if it's older than 3 years)