Change index setting to contacts_index and rename some stuff for clarity

[rowanseymour]

No description provided.

[codecov]

Codecov Report

Merging #55 (2970fd3) into main (ca472f4) will increase coverage by 1.32%.
The diff coverage is 100.00%.

❗ Current head 2970fd3 differs from pull request most recent head 8914509. Consider uploading reports for the commit 8914509 to get more accurate results

@@            Coverage Diff             @@
##             main      #55      +/-   ##
==========================================
+ Coverage   74.39%   75.72%   +1.32%     
==========================================
  Files           3        3              
  Lines         246      243       -3     
==========================================
+ Hits          183      184       +1     
+ Misses         37       35       -2     
+ Partials       26       24       -2     

Impacted Files	Coverage Δ
indexers/base.go	80.43% <100.00%> (+1.71%)	⬆️
indexers/contacts.go	80.35% <100.00%> (+1.59%)	⬆️

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