schema: Remove satellite field from DemodData model
The database schema, here specifically the DemodData model, should be redesigned to make it easier to create a proper API.
The DemodData model has satellite and transmitter fields in DemodData but the transmitter also has a satellite field (as FK) creating a circular relationship.
To fix this the satellite field should be removed from the DemodData model.
- Simplify the database schema
- Remove the circular relationship
- Prevent data corruption cases in which DemodData.satellite != DemodData.transmitter.satellite