chore: checkstyle formater & linter

[jeromevdl]

Issue #, if available: #1290

Description of changes:

• Creation of a checkstyle.xml file (based on google_checks, with custom severities)
• Applied it to the whole project (looooooots of changes)

Checklist

• Meet tenets criteria
• Update tests
• Update docs ==> describe how to use that in CONTRIBUTORS guide (in intelliJ) ==> Docs: Add & improve community documentation #1295
• PR title follows conventional commit semantics

Breaking change checklist

RFC issue #:

• Migration process documented
• Implement warnings (if it can live side by side)

By submitting this pull request, I confirm that you can use, modify, copy, and redistribute this contribution, under the terms of your choice.

[msailes]

They look like sensible suggestions and the license header is cool

[codecov-commenter]

Codecov Report

❌ Patch coverage is 69.70199% with 183 lines in your changes missing coverage. Please review.
✅ Project coverage is 79.35%. Comparing base (baa3592) to head (32ac662).
⚠️ Report is 628 commits behind head on main.

Files with missing lines	Patch %	Lines
...ls/logging/internal/AbstractJacksonLayoutCopy.java	0.00%	62 Missing ⚠️
.../powertools/logging/internal/LambdaJsonLayout.java	0.00%	32 Missing ⚠️
...owertools/logging/internal/JacksonFactoryCopy.java	0.00%	19 Missing ⚠️
...tools/idempotency/internal/IdempotencyHandler.java	30.43%	16 Missing ⚠️
...ertools/cloudformation/CloudFormationResponse.java	73.80%	10 Missing and 1 partial ⚠️
...zon/lambda/powertools/idempotency/Idempotency.java	63.63%	3 Missing and 1 partial ⚠️
...powertools/idempotency/persistence/DataRecord.java	33.33%	2 Missing and 2 partials ⚠️
...lambda/powertools/parameters/DynamoDbProvider.java	66.66%	4 Missing ⚠️
.../lambda/powertools/parameters/SecretsProvider.java	50.00%	4 Missing ⚠️
...powertools/sqs/internal/SqsLargeMessageAspect.java	89.74%	2 Missing and 2 partials ⚠️
... and 16 more

Additional details and impacted files

@@             Coverage Diff              @@
##               main    #1316      +/-   ##
============================================
- Coverage     79.65%   79.35%   -0.31%     
- Complexity      639      641       +2     
============================================
  Files            73       73              
  Lines          2345     2446     +101     
  Branches        253      253              
============================================
+ Hits           1868     1941      +73     
- Misses          397      425      +28     
  Partials         80       80              

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

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[scottgerring]

Can you add something brief in the maintainers guide to this now, because the big maintainers refactor is going to take a bunch of effort and it would be good to capture this requirement quickly now rather than blocking on that.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
24 Code Smells

No Coverage information
0.0% Duplication

[scottgerring]

LGTM