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.
{
    if (request.fHelp || request.params.size() < 1 || request.params.size() > 2) {
        throw std::runtime_error(
            "createwallet \"wallet_name\" ( disable_private_keys )\n"
            "\nCreates and loads a new wallet.\n"
            "\nArguments:\n"
            "1. \"wallet_name\"          (string, required) The name for the new wallet. If this is a path, the wallet will be created at the path location.\n"
            "2. disable_private_keys   (boolean, optional, default: false) Disable the possibility of private keys (only watchonlys are possible in this mode).\n"
            "\nResult:\n"
            "{\n"
            "  \"name\" :    <wallet_name>,        (string) The wallet name if created successfully. If the wallet was created using a full path, the wallet_name will be the full path.\n"
            "  \"warning\" : <warning>,            (string) Warning message if wallet was not loaded cleanly.\n"
            "}\n"
            "\nExamples:\n"
            + HelpExampleCli("createwallet", "\"testwallet\"")
            + HelpExampleRpc("createwallet", "\"testwallet\"")
        );
    }
    std::string wallet_name = request.params[0].get_str();
    std::string error;
    std::string warning;
    bool disable_privatekeys = false;
    if (!request.params[1].isNull()) {
        disable_privatekeys = request.params[1].get_bool();
    }
    fs::path wallet_path = fs::absolute(wallet_name, GetWalletDir());
    if (fs::symlink_status(wallet_path).type() != fs::file_not_found) {