[WIP] improve internal error handling

[kyscott18]

This pr improves the internal error handling of Ponder. Ponder needs to have strictly defined error behavior, exit codes dependent on errors, and useful error logs.

New approach

• BaseError that designates a recognized error within Ponder. Every error that isn't an instance of BaseError is an unexpected error (bug).
• Errors are chained together with the "cause" property when errors change across module boundaries.
• A new error class is only defined when it is meaningful and necessary.
• Stack traces are only printed in errors if it points to user code or is unrecognized.

Remaining

• ShutdownError