Change Notary request senders and try to deduplicate main transactions in auto-deploy procedure about neofs-node HOT 3 OPEN

To clarify things a bit, this issue is mostly related to the currently implemented update procedure.

N nodes will send N requests in total

It's not exactly true. In simultaneous setup scenario current code works in the following way: N nodes will send N*N notary requests in total with N unique main transactions. This happens because we use single signature account (alphabet's one) as the first signer to construct main transaction.

I've firstly suggested to use Proxy contract instead of a single alphabet account as the first signer to reduce the number of unique main transactions (up to one unique main transaction per contract update), but as Leo mentioned, we have a problem with the rest hashable fields synchronisation between the nodes.

From the other side, if we choose some single node to start the update procedure and send initial notary request with update call (the rest of the nodes will track the incoming notary requests and sign them), then the following problem occurs: we don't know how to definitely and reliably choose this single node who will send the first request so that we're 100% sure that exactly one node will init the update process for the subsequent contract.

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Another problem that occurs within the scope of this issue is that the usage of Proxy contract as the first signer isn't possible for deployment procedure, because there's no Proxy contract at this stage.

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how to make main transactions exactly the same (vub/nonce)?

VUB = last_epoch_update_block + something (likely it'll fit into MVUBI)
nonce = epoch

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