Finish switching to use slog for logging

[norkans7]

contains #63

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 22 lines in your changes are missing coverage. Please review.

Project coverage is 52.15%. Comparing base (722ae71) to head (70f293d).

Files	Patch %	Lines
cmd/rp-indexer/main.go	0.00%	22 Missing ⚠️

Additional details and impacted files

@@             Coverage Diff             @@
##             main      #64       +/-   ##
===========================================
- Coverage   67.80%   52.15%   -15.65%     
===========================================
  Files           4        6        +2     
  Lines         410      533      +123     
===========================================
  Hits          278      278               
- Misses        107      230      +123     
  Partials       25       25               

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.