Add lint: systems with conflicting queries

[BD103]

Bevy does not let systems break Rust's mutability rules, and will panic if two queries overlap:

// Will panic: an entity could have both `Player` and `Enemy` components.
fn randomize_health(
    player_query: Query<&mut Health, With<Player>>,
    enemy_query: Query<&mut Health, With<Enemy>>,
) {
    // ...
}

Due to limitations in Rust and how Bevy is architected, conflicts are a runtime error and not a compile-time error.

To provide a better development experience, the linter should error against conflicting queries. Query conflicts are computed with the private assert_component_access_compatibility() function, so we may also be able steal permanently borrow some logic from that.