chore: rename Zeiberg calibrations to ExCALIBR across the codebase

[bencap]

This pull request renames all references to the "Zeiberg calibration" software and related code to "ExCALIBR calibration" throughout the codebase. This includes updates to function names, class names, documentation, test cases, and user-facing strings.

Core library and API changes:

• Renamed all functions and classes related to Zeiberg calibration to use the "ExCALIBR" name, such as zeiberg_calibration_agent → excalibr_calibration_agent, zeiberg_calibration_contribution → excalibr_calibration_contribution, and zeiberg_calibration_method → excalibr_calibration_method. Updated associated descriptions and references to match the new name. [1] [2] [3]

• Updated import statements and usage throughout the codebase to reference the new "ExCALIBR" functions and classes, ensuring all code now uses the new naming convention. [1] [2] [3] [4] [5]

Script and user-facing changes:

• Modified the load_pp_style_calibration.py script to update all user-facing strings, argument help texts, and calibration naming conventions from "Zeiberg calibration" to "ExCALIBR calibration." Also updated variable names and citation constants accordingly. [1] [2] [3] [4] [5] [6]

Test updates:

• Updated all related test cases to use the new "ExCALIBR" function and class names, as well as updated expected string values and assertions to match the new naming and descriptions. [1] [2] [3] [4] [5]