The `generate` RPC method:
- was introduced in 2010
- is now only used for testing
- reaches across multiple components (wallet, mining)

I propose we remove the wallet `generate` RPC method and update all tests to use the `generatetoaddress` RPC method. We can do this non-invasively in the test framework by adding a `generate` method to `TestNode` so that the individual tests do not need to be updated. We could also add a `generate` alias to the `generatetoaddress` RPC method.

Doing this removes a wallet->server dependency and simplifies the wallet->server interface (#10973).

I'm opening this issue before implementing in case anyone has objections.
std::vector<std::string> keys = sendTo.getKeys();
    for (const std::string& name_ : keys) {
        CTxDestination dest = DecodeDestination(name_);
        if (!IsValidDestination(dest)) {
            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, std::string("Invalid Bitcoin address: ") + name_);
        }
        if (destinations.count(dest)) {
            throw JSONRPCError(RPC_INVALID_PARAMETER, std::string("Invalid parameter, duplicated address: ") + name_);
        }
        destinations.insert(dest);
        CScript scriptPubKey = GetScriptForDestination(dest);
        CAmount nAmount = AmountFromValue(sendTo[name_]);
        if (nAmount <= 0)
            throw JSONRPCError(RPC_TYPE_ERROR, "Invalid amount for send");
        totalAmount += nAmount;
        bool fSubtractFeeFromAmount = false;
        for (unsigned int idx = 0; idx < subtractFeeFromAmount.size(); idx++) {
            const UniValue& addr = subtractFeeFromAmount[idx];
            if (addr.get_str() == name_)
                fSubtractFeeFromAmount = true;
        }
        CRecipient recipient = {scriptPubKey, nAmount, fSubtractFeeFromAmount};
        vecSend.push_back(recipient);
    }
    EnsureWalletIsUnlocked(pwallet);
    
    if (totalAmount > pwallet->GetLegacyBalance(ISMINE_SPENDABLE, nMinDepth)) {
        throw JSONRPCError(RPC_WALLET_INSUFFICIENT_FUNDS, "Wallet has insufficient funds");
    }