Make re-ordering issues in boards a more "serious" action

• In board lists, you can re-order issues.
• This is a powerful feature for prioritization.
• But often it's not clear to people that when you move an issue around, that order is stored into the system and actually affects relative ordering.
• Ultimately we want to make it easy for people to re-order issues, but we want to make it clear to people that if they re-order an issue, it will impact the system and other users in how they view the board.
• I don't think we should introduce any additional permissions to restrict issue re-ordering to certain roles. But I do think we should make it more clear in the UI that re-ordering is a big deal, and not to do it lightly because it impacts the system and other users.