Drop notary-less code and data from all contracts except mainnet one

[roman-khimov]

We can have notary subsystem on all public chains now and every private installation also uses it anyway, so notary-less code is only needed for the mainnet neofs contract. Some preliminary work has been done for this in the enable-notary-in-public-chains branch (https://github.com/nspcc-dev/neofs-contract/tree/enable-notary-in-public-chains), but it needs to be extended. The most important thing here is to ensure smooth migration to notary-enabled reality (including notary deposits and the proxy contract that is completely missing in non-notary setups).

[roman-khimov]

• alphabet contract migration cost should add notary deposits for all IR and SNs
• it also should send a half of its GAS to the proxy contract (assuming it's pre-deployed)
• all contracts should check for their voting data to not contain any ongoing votes (panicing otherwise)
• old voting data must be dropped
• notaryDisabled settings must be dropped (except for _deploy parameters, it's cheaper to have them there for now to keep neofs-adm compatibility)

It's one-way migration. Contracts are to be tested using real mainnet data (hi, #281).