Create banner on web app to show "latest available data"

[sidetrackedmind]

Issue

Currently, it's impossible to tell the extent of historical data in S3 from the web app. A user may select dates outside the available range without knowing.

Goal

Create an indicator on the web app showing what data range is available. Something as simple as "Data available from 2022-03-01 to 2022-03-17" on the app somewhere. I think this could be by querying S3 and seeing the min/max available dates that have "observed-stats".

[sidetrackedmind]

There's a last_complete_date key in a json object in S3 - s3://opentransit-pdx/metrics-state/v1/metrics-state_v1_trimet.json.
We need to create a first_complete_date key and store in the same json. Then the banner would grab these dates and display them.

[sidetrackedmind]

dependent on - #24

[erikjasso]

Status for Issue 17

Done:

• write function that fetches data from a URL (fetchDataRange)
• add fetchDataRange() to props
• call fetchDataRange() from screens that use date picker (Dashboard and RouteScreen)

To do:

• use real data
• add tooltip to date picker indicating range of data
• disable dates outside valid range

[erikjasso]

Updated status for Issue 17

Done:

• fetch data from S3

To do:

• add tooltip to date picker indicating range of data
• disable dates outside valid range