Disabling basic income settlements

[alexvanin]

To manage basic income settlements we have BasicIncomeRate parameter of the system.

neofs-api/netmap/types.proto

Lines 265 to 268 in 813c04b

	// - **BasicIncomeRate** \
	// Cost of storing one gigabyte of data for a period of one epoch. Paid by
	// container owner to container nodes.
	// Value: little-endian integer. Default: 0.

Setting it to zero minimize single basic income settlement to 0.000000000001 GAS.

https://github.com/nspcc-dev/neofs-node/blob/d8d3588e1b824af37c34f16bef89e5a2af71f70b/pkg/innerring/processors/settlement/basic/collect.go#L103-L105

	if price.Cmp(bigZero) == 0 {
		price.Add(price, bigOne)
	}

Transfers are still going to persist in the side chain. Private installations might want to decrease number of transactions in sidechain and avoid possible errors in Inner Ring if transfer is going to fail. To do that we should be able to turn off basic income completely.

Possible solutions

1. Add new system parameter BasicIncomeDisabled
2. Interpret zero value of BasicIncomeRate to disable basic income settlements

/cc @realloc @fyrchik

[roman-khimov]

I'd say this can be handled in node, zero rate is zero rate, it's already defined in the protocol and the node should just follow this setting.