[Lake][Subgraph][App] Update app/ & drop: PredictSlot and subgraph. Use Slot & lake.

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Background / motivation

There are various functions inside app + subgraph, that are queryng directly from subgraph + are using an object/data schema called PredictSlot.

This was causing some conflicts w/ lake, and the object that we're using there: "Slot".

Generally, we want to be building functionality that queries from the lake... and wherever that's not possible, to query from an API (that is yet to be built).

In the current cases:

• pdr-backend/app

Is still using PredictSlot, and it looks like all hooks/information, is there to mainly support app/ which to-this-day, still powers the predictoor.ai frontend.

TODOs / DoD

1. Reconcile these two things so we have 1 object: Slot
2. Move everything to query/get data from the lake (or a remote API)
3. Port/Update all the work inside of app/elsewhere that's using Subgraph + Predict Slot => To use Lake + Slot
4. Remove/Drop all usage of PredictSlot
5. Have all exterior facing systems querying from the lake

Tasks:

• Stop using PredictSlot and drop it from code
• Stop querying the subgraph for answers related to Slots, use the lake instead
• Update APP to query from the lake's "Slot" table, to provide information
• Update other APIs in app/ to serve the correct information from the lake
• Write README.md on how to deploy server, update lake, and leave lake updating
• Write README.md for how to test the server, to make sure that it's working and updating correctly
• Make sure that predictoor.ai FE is still working using latest implementation that's serving from lake

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Please close when #1048 is complete