[Accuracy] Address implementation and cleanup issues inside app.py

[idiom-bytes]

Is your feature request related to a problem? Please describe.
There have been a bunch of feedback provided to app.py in #1421 so it can be improved. The PR mentioned above didn't modify app.py, much of the feedback provided is still valid.

Please use this ticket to cleanup/improve app.py

Describe the solution you'd like
Please review the feedback provided in #1421 and address all issues

DoD:

• app.py implements a low-quality infinite loop while true
• if predictSlot is being deprecated and we're only using the lake, then update the code to deprecate wherever appropriate and only use Slot
• fix lambda function
• use UnixTimeS and correct time_type functions to achieve correct timestamp calculations
• use duckdb to do ETL work and avoid going between sql->py->sql->py as this is horribly inneficient
• move slots functionality to Slots object
• improve exception handling and code