minor updates for RocketLaunchLive API

[DJDevon3]

Using newer time_calc function, relabeled some variables, fixed os.getenv defaults for CIRCUITPY_ variables. made sleep_time shouty. board uptime displays time_calc human readable instead of monotonic seconds.

Discovered Rocket Launch Open, Close, and T-Zero window can be a combination of any of the 3. Sometimes there's an open and close window, sometimes there's only a T-Zero, sometimes there's a Window Open and T-Zero, sometimes T-Zero and Window Close... Sometimes they include T0 in the time... So just accounted for all the possibilities and call it done. If one, more, or all of the variables are None or aren't used then it won't be displayed.

Tested and reconfirmed everything works as it should

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Connecting to WiFi...
✅ Wifi!
 | Attempting to GET RocketLaunch.Live JSON!
 | ✅ RocketLaunch.Live JSON!
 |  | Date: Mar 25
 |  | Flight: Starlink 6-46
 |  | Provider: SpaceX
 |  | Vehicle: Falcon 9
 |  | Window: 2024-03-25T21:00Z | 2024-03-26T01:31Z
 |  | Site: Cape Canaveral SFS
 |  | Pad: SLC-40
 |  | Description: A SpaceX Falcon 9 rocket will launch the Starlink 6-46 mission on Monday, March 25, 2024 at 9:00 PM (UTC).
✂️ Disconnected from RocketLaunch.Live API

Finished!
Board Uptime: 21 minutes
Next Update: 12 hours
===============================

[FoamyGuy]

Looks good to me. I tested it successfully on a Feather S3 TFT. Thank you!