Minor docs IA clean up

[daniel-prefect]

Closes https://linear.app/prefect/issue/DOC-93/segment-documentation-by-type-and-persona

• "Resources" is a bit of a miscellaneous grab bag of topics right now. To fix this:
  • Rename this group to "Migrate" to align with the verb theme we use for the other top-level sections
  • Redistribute the topics that don't pertain to migration to the relevant sub-sections under Develop and Deploy.
• Rename the "Cloud and server" section to "Operate" since it's the closest thing we have to an Operator focused section in the docs right now (and "Operate" fits better with the verb theme we use for the other top-level sections)

Checklist

• This pull request references any related issue by including "closes <link to issue>"
• If this pull request adds new functionality, it includes unit tests that cover the changes
• If this pull request removes docs files, it includes redirect settings in mint.json.
• If this pull request adds functions or classes, it includes helpful docstrings.

[discdiver]

lgtm. Thank you!