Identify failed DAC scans

Description

This merge request enhances the identification of failed DAC scans. In particular,

• fit each scan with a 5-th degree polynomial, compute its chi^2, and apply a pre-computed cut;
• check that the scans are monotonic;
• display scans with warnings more evidently.

The first two commits implement additional fixes:

1. Ensure an error message is displayed when an exception is thrown in the multiprocessing.Pool worker threads.
2. Properly define the out-of-range warning.

Related Issue

Fixes #49 (closed).

How Has This Been Tested?

Tested in a local development environment with multiple sets of DAC scans (first one taken on 26/02/2024).

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.