Ordering issues with associative array

[Voltra]

Fix ordering issues by using regular arrays instead of associative arrays. Existing code should work as is, thanks to PHP handling both kinds of arrays the same way.

This is a proposition of fix that highlights a problem: There's an issue with sorting.

Sorting is always correct when done in the create/edit view. But once saved and reloaded, the items were sorted by UUID (i.e. by array keys) instead of keeping their manually attributed order.

[Voltra]

My guess is that since JSON objects are unordered sets of name/value pairs, there's no guarantee it'll keep ordering across systems (e.g. PHP-level serde, DB-level serde)