chore(relint): relint code base

[fredbi]

• strengthen golangci rules: closer to full alignment with other go-openapi repos
• relint all
• readability: refactor complex methods & functions

Change type

Please select: 🆕 New feature or enhancement|🔧 Bug fix'|📃 Documentation update

Short description

Fixes

Full description

Checklist

• I have signed all my commits with my name and email (see DCO. This does not require a PGP-signed commit
• I have rebased and squashed my work, so only one commit remains
• I have added tests to cover my changes.
• I have properly enriched go doc comments in code.
• I have properly documented any breaking change.

[codecov]

Codecov Report

❌ Patch coverage is 68.46591% with 111 lines in your changes missing coverage. Please review.
✅ Project coverage is 83.14%. Comparing base (d5b684b) to head (ec716a1).
⚠️ Report is 2 commits behind head on master.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
middleware/context.go	72.07%	25 Missing and 6 partials ⚠️
middleware/parameter.go	74.03%	16 Missing and 11 partials ⚠️
middleware/router.go	51.28%	13 Missing and 6 partials ⚠️
internal/testing/simplepetstore/api.go	40.74%	8 Missing and 8 partials ⚠️
client/internal/request/request.go	63.63%	2 Missing and 2 partials ⚠️
client/tls.go	0.00%	4 Missing ⚠️
middleware/validation.go	84.00%	4 Missing ⚠️
internal/testing/petstore/api.go	60.00%	1 Missing and 1 partial ⚠️
middleware/request.go	71.42%	2 Missing ⚠️
client/runtime.go	0.00%	1 Missing ⚠️
... and 1 more

Additional details and impacted files

@@            Coverage Diff             @@
##           master     #461      +/-   ##
==========================================
- Coverage   83.45%   83.14%   -0.32%     
==========================================
  Files          62       62              
  Lines        4388     4473      +85     
==========================================
+ Hits         3662     3719      +57     
- Misses        567      582      +15     
- Partials      159      172      +13     

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