Reorg jetstream into deep dives folder, add autogeneration for sidebar. Small FAQ cleanup.

[eliserichards]

• Putting the /jetstream folder within /deep-dives since that's where it lives in the sidebar
• The jetstream sidebar was manually created, so there was a missing file that wasn't previously being shown in the sidebar: deep-dives/jetstream/adding-a-platform
• Made the jetstream folder autogenerated
• Added sidebar_position to each of the docs to mimic the current order
• Simplified some of the sidebar labels
• Rename data-scientists-root to overview
• Fix links

Before vs after: