This ticket is for adding move-to-archive functionality for Special:EnableFlow.

The current v1 EnableFlow lets us create a Flow board on a page that doesn't exist (or has been deleted).

For v2, we want to be able to put a Flow board on an existing wikitext page -- moving the wikitext page to an archive, and creating a Flow board in its place.

The v2 tool should have a field where we can specify the archive location.

Later revs will include disabling (and un-archiving) (T96301: Solution for disabling Flow on a page), and being able to enable Flow on multiple pages or on a namespace (not yet filed).

Some related concepts broken out to T96302: Enable Flow on a single wikitext talk page that already exists, choosing archive name and handling archiving automatically, T96301: Solution for disabling Flow on a page, and T96304: Validate which Flow moves are allowed?

Formerly part of https://trello.com/c/0VP635yr/