Add time-behind path

[thieflord06]

Is your feature request related to a problem? Please describe.
This feature shows how "far behind" Clearsky's data is from real-time.

Describe the solution you'd like
The "time behind" feature was implemented when the UI was powered by the python web server, we have stripped the python out and now purely react. This feature needs to be added back.

The original path was data.clearsky.app which was being handled by DNS to redirect to /data-sync. The goal is to handle this in app if possible.

Describe alternatives you've considered

Additional context
Attached is the frontend code that was being used. Creative freedom is welcomed.

apiServerEndpoint needs to dynamically switch between appropriate backends.

time_behind_code.txt

[thieflord06]

This is what it looked like:

[thieflord06]

As a stop gap I've added it to the backend: https://staging.api.clearsky.services/data-sync

[thieflord06]

This looks like it's already implemented under /data-status and I have added the DNS handling for data.clearsky.app but this needs to be transitioned to in app handling.