Add a "Maintain" to the information architecture

[lisa-parity]

Part of the original scaffolding, but not included in v1 of the new docs.substrate.io site. We can add potential source material references and ideas to this issue.

Provide better documentation regarding how to maintain the operational stability of a Substrate-based chain. Topics may include: launching and maintaining operators, sentries, bootnodes, RPC pools and more.

Ref: https://wiki.polkadot.network/docs/en/maintain-index

Builders program devops office hour: video https://drive.google.com/file/d/1-nQ_SI2XK6vxPQvORWuv68Yj0UDz5FrO/view notes: https://gist.github.com/lovelaced/cddc1c7234b883ee37e71cf4a1d63cac surface services to consider: https://monk.io/ (SBP video... recording where?) https://www.onfinality.io/

https://github.com/substrate-developer-hub/substrate-docs/issues/169