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.
+ HelpExampleRpc("getnewaddress", "")
        );
    if (pwallet->IsWalletFlagSet(WALLET_FLAG_DISABLE_PRIVATE_KEYS)) {
        throw JSONRPCError(RPC_WALLET_ERROR, "Error: Private keys are disabled for this wallet");
    }
    LOCK(pwallet->cs_wallet);
    
    std::string label;
    if (!request.params[0].isNull())
        label = LabelFromValue(request.params[0]);
    OutputType output_type = pwallet->m_default_address_type;
    if (!request.params[1].isNull()) {
        if (!ParseOutputType(request.params[1].get_str(), output_type)) {
            throw JSONRPCError(RPC_INVALID_ADDRESS_OR_KEY, strprintf("Unknown address type '%s'", request.params[1].get_str()));
        }
    }
    if (!pwallet->IsLocked()) {
        pwallet->TopUpKeyPool();
    }
    
    CPubKey newKey;
    if (!pwallet->GetKeyFromPool(newKey)) {
        throw JSONRPCError(RPC_WALLET_KEYPOOL_RAN_OUT, "Error: Keypool ran out, please call keypoolrefill first");
    }
    pwallet->LearnRelatedScripts(newKey, output_type);
    CTxDestination dest = GetDestinationForKey(newKey, output_type);
    pwallet->SetAddressBook(dest, label, "receive");
    return EncodeDestination(dest);
}
static UniValue getrawchangeaddress(const JSONRPCRequest& request)