When using price included taxes, the xml contained data that failed to
meet the constraints of the edi. This is due to the local rounding on
the lines of the invoice.
For example:

	A product costing 321€, on two lines of the invoice, with
	a price included tax of 22%
	Rounded per line:
	float_round(
		321 - (321/122 * 100),
		2 # To two decimal places
	)
	evaluates to 57.89, the total tax will be 2 * 57.89 = 115.78

	In the case of global rounding
	float_round(
		321 + 321 - (321/122*100) - (321/122*100),
		2 # To two decimal places
	)
	evaluates to 115.77,

	so we have a difference of one cent.

This can be exacerbated by more lines.

The constraints on the EDI that this conflicts with are on the tax
summary section for each tax.
The constraints (roughly reworded):
00422:  The base taxable amount for the tax must be equal to the sum of
	the base product prices (for which we have already used the
	rounded computed values, calcuated in the invoice) +
	<Arrotondamento> (rounding).

00421:  The value provided for the <importo> that is the value of the
	vat is equal to the taxable base multiplied by the tax rate.

The problem is that because of our local roundings, the taxable base
is equal to our products, but the tax rate * taxable base is not equal
to the tax amount (as present in the invoice).

This commit adds to the rounding field and subtracts from the
taxable base of the tax summary a value rounding value that
should make tax rate * taxable base equal to the value of the vat.

task: 2789290

Forward-Port-Of: odoo/odoo#86052