Speed up JBrowse RefSeqs endpoint

[njbooher]

This pull request addresses issue #345

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[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
0.0% Duplication

[codecov-commenter]

Codecov Report

Merging #346 (45a1b14) into master (22b0b1d) will decrease coverage by 0.01%.
The diff coverage is 0.00%.

@@            Coverage Diff             @@
##           master     #346      +/-   ##
==========================================
- Coverage   66.49%   66.47%   -0.02%     
==========================================
  Files          30       30              
  Lines        4214     4215       +1     
  Branches      730      730              
==========================================
  Hits         2802     2802              
- Misses       1349     1350       +1     
  Partials       63       63              

Impacted Files	Coverage Δ
machado/api/serializers.py	0.00% <0.00%> (ø)
machado/api/views.py	0.00% <0.00%> (ø)

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[njbooher]

fixed formatting