Use vector implementation for `calc_alan_entries()`

[smokestacklightnin]

:pencil: Description

Type: :rocket: feature

Use vectorized implementations for the body of calc_alan_entries().

:vertical_traffic_light: Testing

How did you test these changes?

• [X] Testing pipeline

:ballot_box_with_check: Checklist

• [x] I requested two reviewers for this pull request
• [ ] I updated the documentation according to my changes

[codecov[bot]]

Codecov Report

Merging #140 (0adf5b8) into main (afcc0ca) will increase coverage by 4.26%. The diff coverage is 16.66%.

:exclamation: Current head 0adf5b8 differs from pull request most recent head 39e0fe5. Consider uploading reports for the commit 39e0fe5 to get more accurate results

@@            Coverage Diff             @@
##             main     #140      +/-   ##
==========================================
+ Coverage   68.19%   72.45%   +4.26%     
==========================================
  Files          27       27              
  Lines         984      864     -120     
==========================================
- Hits          671      626      -45     
+ Misses        313      238      -75     

Files	Coverage Δ
...adiation_field/opacities/opacities_solvers/base.py	82.22% <16.66%> (+0.90%)	:arrow_up:

... and 6 files with indirect coverage changes

:mega: Codecov offers a browser extension for seamless coverage viewing on GitHub. Try it in Chrome or Firefox today!