[BUG] Fix exception pickling (cause of TypeError => BrokenProcessPool).

[Sam Fakhreddine]

Description: [BUG] Fix exception pickling (cause of TypeError => BrokenProcessPool).

[mbordash2]

@ITProKyle to fix one as an example.

[Kyle Finley]

Heres an example of what needs to be done for all custom exceptions in the runway codebase:

1. All arguments must be positional.
2. If more than one argument is accepted, a __reduce__ method must be added (example __reduce__ method plus a unit test for the exception).

The base classes RunwayError and CfnginError are fine as written.