refactor(catalog): extract fetcher and caching into dedicated classes with stale-while-revalidate strategy

[SEQUOIIA]

… with stale-while-revalidate strategy

closes dfds/cloudplatform/issues/pr-issue-number

Additional Review Notes

Put your complementary notes here for helping reviewers review your changes.

[DFDS-Snyk]

✅ Snyk checks have passed. No issues have been found so far.

Status	Scan Engine	Critical	High	Medium	Low	Total (0)
✅	Open Source Security	0	0	0	0	0 issues
✅	Licenses	0	0	0	0	0 issues
✅	Code Security	0	0	0	0	0 issues

💻 Catch issues earlier using the plugins for VS Code, JetBrains IDEs, Visual Studio, and Eclipse.