Add a balance tier between Ӿ0.000001 and Ӿ0.0003

[keerifox]

Currently

nano-node/nano/node/scheduler/buckets.cpp

Lines 42 to 51 in 254aa88

	minimums.push_back (uint128_t{ 0 });
	build_region (uint128_t{ 1 } << 88, uint128_t{ 1 } << 92, 2);
	build_region (uint128_t{ 1 } << 92, uint128_t{ 1 } << 96, 4);
	build_region (uint128_t{ 1 } << 96, uint128_t{ 1 } << 100, 8);
	build_region (uint128_t{ 1 } << 100, uint128_t{ 1 } << 104, 16);
	build_region (uint128_t{ 1 } << 104, uint128_t{ 1 } << 108, 16);
	build_region (uint128_t{ 1 } << 108, uint128_t{ 1 } << 112, 8);
	build_region (uint128_t{ 1 } << 112, uint128_t{ 1 } << 116, 4);
	build_region (uint128_t{ 1 } << 116, uint128_t{ 1 } << 120, 2);
	minimums.push_back (uint128_t{ 1 } << 120);

I'm unable to compute the code above at the moment, but to my knowledge the current balance tiers start with the following:

#1 – Ӿ0 to Ӿ0.0003
...

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Proposal

The proposal is to add another tier to have the following:

#1 – Ӿ0 to Ӿ0.000000999
#2 – Ӿ0.000001 to Ӿ0.0003
...

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Why

Many faucets send less than Ӿ0.0003 to accounts trying out nano for the first time, and many users send less than Ӿ0.0003 as a test transaction to see if the destination account is valid and is able to receive transactions. When receiving said amount on a newly created account, the receive transaction will have approximately the same priority as so-called "dust transactions" between Ӿ0 and Ӿ0.000001, and thus at best the first impression of the user might be negatively affected, and at worst their account might be temporarily prevented from performing important transactions as they would need to wait until the receive transaction confirms or is dropped.

Ӿ0.000001 is the minimum amount that some wallets allow to enter with a number input, and is also the minimum amount for automatic receives. Currently accounts with 0 balance might receive an incoming transaction of Ӿ0.000001 and the wallets might automatically receive them – this might create further delay to transactions that the user planned to do.