Add lint: panicking ECS APIs

[alice-i-cecile]

Calling .single, .single_mut, .resource, .resource_mut and so on can introduce surprising crashes to your production game.

We should pair this with a recommendation to use equivalent lints around unwrap and expect in clippy, so coders don't just change .single() to .get_single().unwrap().

We probably want to split this into two lints, one for query data and the other for resources.

[BD103]

Thank you! Marking this as a duplicate of #58 and copying over your comment there.