[FIX] point_of_sale: factorization of _create_account_move
[FIX] point_of_sale: factorization of _create_account_move

This factorization is needed for support purpose.
I.E.: This will allow to post an account move to balance
unbalanced journal entries.

Basically, it divides the function into sections
that were already present in comments.

closes odoo/odoo#45231

X-original-commit: 26e012015a6803af6c2a5480984f1c02e0244e83
Signed-off-by: Nicolas Martinelli (nim) <771435c469f83f6aa9c405ac5e1ed06314a94f2d@odoo.com>

ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo