feat: make k8Secrets auth provider secret cache TTL configurable

[ramasai1]

Description

Make the cache TTL for k8Secrets provider configurable.

Which issue(s) does this PR resolve?

Fixes #2580

Type of change

• New feature (non-breaking change which adds functionality)
• Helm chart change (any edit/addition/update that is necessary for changes merged to the main branch)

Testing and verification

Unit tests.

Checklist

• Does the affected code have corresponding tests?
• Are the changes documented, not just with inline documentation, but also with conceptual documentation such as an overview of a new feature, or task-based documentation like a tutorial? Consider if this change should be announced on your project blog.
• Does this introduce breaking changes that would require an announcement or bumping the major version?
• Do all new files have appropriate license header?

Post merge requirements

• MAINTAINERS: manually trigger the "Publish Package" workflow after merging any PR that indicates Helm Chart Change

[fseldow]

one small comment in doc, others lgtm
cc @susanshi for review or vote from maintainer

[codecov]

Codecov Report

❌ Patch coverage is 60.00000% with 6 lines in your changes missing coverage. Please review.
⚠️ Please upload report for BASE (v1-dev@313fd08). Learn more about missing BASE report.

Files with missing lines	Patch %	Lines
.../common/oras/authprovider/k8secret_authprovider.go	60.00%	4 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff            @@
##             v1-dev    #2581   +/-   ##
=========================================
  Coverage          ?   71.82%           
=========================================
  Files             ?      147           
  Lines             ?     7528           
  Branches          ?        0           
=========================================
  Hits              ?     5407           
  Misses            ?     1735           
  Partials          ?      386           

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[fseldow]

/lgtm