Add vuln data source docs and initial air-gap guide

[nscuro]

No description provided.

[Copilot]

Pull request overview

This PR restructures the documentation around vulnerability data sources by replacing per-datasource reference pages with a consolidated “concepts” explainer and an administration how-to, and adds an initial guide for operating Dependency-Track in air-gapped environments.

Changes:

• Add new conceptual and procedural docs for vulnerability data sources and how to enable/schedule mirroring.
• Add an initial “Running air-gapped” administration guide and wire it into existing docs.
• Remove legacy per-source reference pages (NVD/GitHub advisories/OSV) and update navigation and cross-links accordingly.

Reviewed changes

Copilot reviewed 18 out of 21 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
docs/reference/index.md	Updates reference landing page to point to the new concept + admin guide and the consolidated datasources overview.
docs/reference/datasources/private-vulnerability-repository.md	Reflows/modernizes wording and headings for consistency and readability.
docs/reference/datasources/osv.md	Removes legacy OSV per-source reference page in favor of consolidated docs.
docs/reference/datasources/nvd.md	Removes legacy NVD per-source reference page in favor of consolidated docs.
docs/reference/datasources/internal-components.md	Rewords/normalizes the internal components datasource reference page.
docs/reference/datasources/index.md	Refocuses the datasources overview page and links out to the new concept/admin procedure docs.
docs/reference/datasources/github-advisories.md	Removes legacy GitHub advisories per-source reference page in favor of consolidated docs.
docs/reference/datasources/.pages	Updates datasources navigation to remove the deleted per-source pages.
docs/reference/analyzers.md	Adds a pointer from the internal analyzer reference to the new vulnerability data sources concept page.
docs/guides/administration/running-air-gapped.md	Adds a new (explicitly incomplete) air-gapped operation guide for sources/analyzers.
docs/guides/administration/migrating-from-v4.md	Adds a link to the new vulnerability sources configuration procedure post-migration.
docs/guides/administration/configuring-vulnerability-sources.md	Adds a new step-by-step guide for enabling and mirroring NVD/GitHub/OSV.
docs/guides/administration/configuring-internal-ca.md	Clarifies internal CA trust scenarios for internal mirrors and links to new docs.
docs/guides/administration/configuring-http-proxy.md	Links proxy guidance directly to vulnerability data source configuration.
docs/guides/administration/.pages	Adds the two new administration guide pages to navigation.
docs/concepts/changes-in-v5.md	Links v5 changes doc to the new air-gapped guide for internal mirror hosting.
docs/concepts/about-vulnerability-data-sources.md	Adds a new concept page explaining what each source provides and matching trade-offs.
docs/concepts/.pages	Adds the new concept page to the Concepts navigation.

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.