docs: add concepts section for outlining important OOB pieces

[rsdmike]

PR Checklist

• Leverages formatting as provided by https://squidfunk.github.io/mkdocs-material/reference/abbreviations/
• Have viewed and verified edits in rendered form ensuring proper formatting

What are you changing?

Creates a dedicated concept section to outline important aspects to understand as part of the toolkit. This declutters the "Reference" section a bit.

Anything the reviewer should know when reviewing this PR?

[Copilot]

Pull request overview

This PR reorganizes the documentation by introducing a new Concepts section for key out-of-band (OOB) and foundational topics, reducing the amount of conceptual material living under Reference, and adding a Tutorials landing page to better orient users.

Changes:

• Updates mkdocs.yml navigation to add a top-level Concepts section and a Tutorials > Overview entry.
• Adds new Concepts pages (architecture, OOB management, control modes, security).
• Streamlines Reference/architectureOverview.md by replacing large conceptual blocks with links to the new Concepts pages.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
mkdocs.yml	Adds the Concepts section and Tutorials overview to site navigation; removes duplicated “Get Help” blocks from other tabs.
docs/Tutorials/overview.md	New Tutorials landing page with curated entry points and mkdocs-material button links.
docs/Reference/architectureOverview.md	Refactors content to focus on architecture overview and links out to Concepts/Logging for deeper explanations.
docs/Concepts/architecture.md	New architecture/concepts page consolidating deployment flow, components, and connection models.
docs/Concepts/oobManagement.md	New OOB management concept page (in-band vs OOB, power control, KVM).
docs/Concepts/controlModes.md	New ACM vs CCM control modes concept page plus domain profile notes and related links.
docs/Concepts/security.md	New security overview page with credential guidance and links to component security/cert/secrets references.

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