As a user, I want to move (rename) a page with an associated Flow board, and have the Flow board automatically move with it, the way that talk pages currently do.
As a user, if I use Special:MoveTo to move only a Flow board, that should work too.
==== Acceptance criteria ====
* [] Clicking "Move" in the menu, the Special:MovePage message should have "Move associated Flow board" as an option, replacing the current "Move associated talk page".
* [] Flow should be enabled at the new location, and the topics and header on the old Flow board should be connected to the board's new location.
* [] "Leave a redirect behind" should work. (If the old location is still Flow-enabled we would have to make #REDIRECT work on Flow board or put a soft redirect in its board header).
* [] If the new Flow board location cannot be a Flow board, or the user does not have the rights to enable Flow there, then the move should fail with an appropriate error.
* [] Do we need to re-render?
{F104249}
--------------------------
**Trello card**: [[ https://trello.com/c/V9va2kmj/263-move-a-flow-board-part-of-rollout-vision-discussion | V9va2kmj ]]
* column: Send to Phabricator - Collaboration-Team board