refactor the logger to be a singleton and use init()

[synfinatic]

Cleanup the logger to better follow Go best practices.

Refs: #1001

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.61%. Comparing base (81e0984) to head (c4f5138).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1005      +/-   ##
==========================================
+ Coverage   84.17%   84.61%   +0.43%     
==========================================
  Files          42       34       -8     
  Lines        3071     3040      -31     
==========================================
- Hits         2585     2572      -13     
+ Misses        393      375      -18     
  Partials       93       93              

Flag	Coverage Δ
unittests	84.61% <100.00%> (+0.43%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
internal/ecs/client/client.go	92.98% <100.00%> (+0.13%)	⬆️
internal/ecs/http.go	100.00% <100.00%> (ø)
internal/ecs/server/server.go	92.94% <100.00%> (+0.17%)	⬆️
internal/helper/helper.go	69.61% <100.00%> (+0.61%)	⬆️
internal/predictor/predictor.go	85.11% <100.00%> (+0.32%)	⬆️
internal/sso/logger.go	100.00% <100.00%> (ø)
internal/storage/storage.go	96.43% <100.00%> (+0.13%)	⬆️
internal/tags/logger.go	100.00% <100.00%> (+66.67%)	⬆️
internal/url/url.go	91.03% <100.00%> (+0.12%)	⬆️
internal/utils/utils.go	96.12% <100.00%> (+0.08%)	⬆️

... and 1 file with indirect coverage changes

---

Continue to review full report in Codecov by Sentry.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 81e0984...c4f5138. Read the comment docs.