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() < 1 || request.params.size() > 2)
        throw std::runtime_error(
            "gettransaction \"txid\" ( include_watchonly )\n"
            "\nGet detailed information about in-wallet transaction <txid>\n"
            "\nArguments:\n"
            "1. \"txid\"                  (string, required) The transaction id\n"
            "2. \"include_watchonly\"     (bool, optional, default=false) Whether to include watch-only addresses in balance calculation and details[]\n"
            "\nResult:\n"
            "{\n"
            "  \"amount\" : x.xxx,        (numeric) The transaction amount in " + CURRENCY_UNIT + "\n"
            "  \"fee\": x.xxx,            (numeric) The amount of the fee in " + CURRENCY_UNIT + ". This is negative and only available for the \n"
            "                              'send' category of transactions.\n"
            "  \"confirmations\" : n,     (numeric) The number of confirmations\n"
            "  \"blockhash\" : \"hash\",  (string) The block hash\n"
            "  \"blockindex\" : xx,       (numeric) The index of the transaction in the block that includes it\n"
            "  \"blocktime\" : ttt,       (numeric) The time in seconds since epoch (1 Jan 1970 GMT)\n"
            "  \"txid\" : \"transactionid\",   (string) The transaction id.\n"
            "  \"time\" : ttt,            (numeric) The transaction time in seconds since epoch (1 Jan 1970 GMT)\n"
            "  \"timereceived\" : ttt,    (numeric) The time received in seconds since epoch (1 Jan 1970 GMT)\n"