Extend the use of custom errors and exit codes

Related: https://github.com/runtimeverification/kontrol/pull/279

As @tothtamas28 suggested, we can start building a library of custom exceptions, and, for CLI usage, we can then catch them, print some error message, then exit with the corresponding exit code. We can also have a catch-all case for unhandled exceptions, for which we can do some extra logging and perhaps ask the user to submit a bug report.

This would also help us capture errors more accurately. For example, we should throw an error instead of exiting with code 1 in the following case (right now, if the caller wants to handle that exception (e.g. by translating to an error message on the output), they will be forced to catch SystemExit):

def build(self) -> None:
    try:
        run_process(['forge', 'build', '--root', str(self._root)], logger=_LOGGER)
    except FileNotFoundError:
        print("Error: 'forge' command not found. Please ensure that 'forge' is installed and added to your PATH.")
        sys.exit(1)

Start by reading the related pull request #279 and the build method in src/kontrol/foundry.py around the linked FileNotFoundError case. Trace the CLI entry points that currently handle failures and exit codes. Done means the agreed custom-error and CLI handling scope is implemented with corresponding exit behavior and coverage for the shown failure and unhandled exceptions.