Update messaging interface

[nealkruis]

• Update to new version of Courier (previously known as "Courierr")
• Add name member to RGI for better context in messages
• Standardize message format
• Re-evaluate message severity

[codecov-commenter]

Codecov Report

Attention: 15 lines in your changes are missing coverage. Please review.

Comparison is base (2a5926e) 86.77% compared to head (68d06f3) 92.40%.

Files	Patch %	Lines
src/regular-grid-interpolator-implementation.cpp	76.74%	10 Missing ⚠️
include/btwxt/grid-axis.h	66.67%	2 Missing ⚠️
src/regular-grid-interpolator-implementation.h	0.00%	2 Missing ⚠️
src/grid-axis.cpp	92.31%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #39      +/-   ##
==========================================
+ Coverage   86.77%   92.40%   +5.63%     
==========================================
  Files           7        6       -1     
  Lines         514      487      -27     
==========================================
+ Hits          446      450       +4     
+ Misses         68       37      -31     

Flag	Coverage Δ
integration	92.40% <83.70%> (+5.63%)	⬆️

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