[17.0][MIG] sale_timesheet_rounded: Migration to 17.0

[sonhd91]

Since the idea of this module is to replace the regular unit_amount with unit_amount_rounded by adding it as a field in the read_group method, and then replacing unit_amount with unit_amount_rounded.

In v17, the fields readed and the groupby are hard-coded when dealing with sales order lines, and the static loop element makes implementing the rounded flow prone to bugs. Therefore, I suggest overriding the method _get_delivered_quantity_by_analytic with hooks.