feat: better exceptions and logging and startup

[tiptenbrink]

I was taking a look at the exception logging and found that the stacktrace is not properly logged.

Ideally, we would not also show a lot of the unnecessary Uvicorn/Starlette/FastAPI stacktrace, but I did some exploration and it's not easy at all to remove this if you do want to have the stacktrace of your application. It's best we just live with it.

Throwing an AppError in the application will now log the error and lead to a 500 response.

Other improvements:

• All queries are now performed with execute_catch (renamed form execute_catch_conn) to allow better handling of exceptions. I added a new type of DbError, ProgrammingError based on the SQLAlchemy exception type. This occurs for instance when a table is undefined.
• I added some better error messages for common problems when running the backend, like an incorrect config, or an empty database (this uses the ProgrammingError) or if the database isn't on. It's mostly just heuristics, like I only added the ProgrammingError check for the JWK loading since in practice this is the first time we load something from the DB. Maybe good to replace that in the future with something more structured.
• I added a new command to the dev.nu script, running nu dev.nu backend will now start the backend.
• I renamed StoreError to StoreObjectError and ensured all errors in the store module inherit from a basic StoreError.
• Connections are now terminated when recreating a database.
• I added some additional documentation to some functions that return errors and made the language clearer on the startup lock.

[SenneDrent]

👍

[SenneDrent]

👍