Remove number from account move
The number on account move is generated from a sequence from the journal. It is a temporary number until the move is posted then it will receive a post number.
Indeed this design has strong constraint as it prevent to modify the journal of a move once it is saved, see #8884 (closed). Also having such numbering per journal is not really useful and it is more an heritage of manual accounting on paper.
So I propose to remove the number and the sequence on journal and to rename the post number to number.
For the record name of draft move, I propose to use the (id) as we do for other documents (like invoice, sale etc.)