style: go fmt cleanup

v0.10.2 - Code Organization Refactor

Split monolithic simples3.go into logical modules for better maintainability:
- simples3.go (core): S3 struct, config, signing
- iam.go: IAM credential handling and token renewal
- list.go: List operations with pagination iterator
- object.go: File operations (upload, download, delete, details)
- helpers.go: Utility functions

No API changes. 100% backward compatible.

feat: Add support for `response-content-disposition` in presigned URLs (

#34)

* feat: add support for response-content-disposition in presigned URLs
- minor refactors

* remove extra comments

Merge pull request #33 from rhnvrm/feat-listobjects-v2

feat: implement Simple List API for S3 objects

Merge pull request #32 from abhinavxd/patch-1

fix: expired token error while generating presigned URLs

Merge pull request #31 from joicemjoseph/hotfix/iam-imds2-token-renewal

hotfix: corrects renewal logic

Merge pull request #28 from nemunaire/b/signedurl_for_custom_endpoint

Rework presign function to allow signature of clients with dedicated endpoint

Merge branch 'develop'

Merge pull request #25 from rhnvrm/fix-security-token

fix: set token header if available

Merge pull request #21 from rhnvrm/feat-do-support

feat: add support for DigitalOcean