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::shared_ptr<CWallet> const wallet = GetWalletForJSONRPCRequest(request);
    CWallet* const pwallet = wallet.get();
    if (!EnsureWalletIsAvailable(pwallet, request.fHelp)) {
        return NullUniValue;
    }
    if (request.fHelp || request.params.size() > 2) {
        throw std::runtime_error(
            "sethdseed ( \"newkeypool\" \"seed\" )\n"
            "\nSet or generate a new HD wallet seed. Non-HD wallets will not be upgraded to being a HD wallet. Wallets that are already\n"
            "HD will have a new HD seed set so that new keys added to the keypool will be derived from this new seed.\n"
            "\nNote that you will need to MAKE A NEW BACKUP of your wallet after setting the HD wallet seed.\n"
            + HelpRequiringPassphrase(pwallet) +
            "\nArguments:\n"
            "1. \"newkeypool\"         (boolean, optional, default=true) Whether to flush old unused addresses, including change addresses, from the keypool and regenerate it.\n"
            "                             If true, the next address from getnewaddress and change address from getrawchangeaddress will be from this new seed.\n"
            "                             If false, addresses (including change addresses if the wallet already had HD Chain Split enabled) from the existing\n"
            "                             keypool will be used until it has been depleted.\n"
            "2. \"seed\"               (string, optional) The WIF private key to use as the new HD seed; if not provided a random seed will be used.\n"
            "                             The seed value can be retrieved using the dumpwallet command. It is the private key marked hdseed=1\n"
            "\nExamples:\n"
            + HelpExampleCli("sethdseed", "")
            + HelpExampleCli("sethdseed", "false")
            + HelpExampleCli("sethdseed", "true \"wifkey\"")
            + HelpExampleRpc("sethdseed", "true, \"wifkey\"")
            );
    }
    if (IsInitialBlockDownload()) {