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.
"      \"minimumAmount\"    (numeric or string, default=0) Minimum value of each UTXO in " + CURRENCY_UNIT + "\n"
            "      \"maximumAmount\"    (numeric or string, default=unlimited) Maximum value of each UTXO in " + CURRENCY_UNIT + "\n"
            "      \"maximumCount\"     (numeric or string, default=unlimited) Maximum number of UTXOs\n"
            "      \"minimumSumAmount\" (numeric or string, default=unlimited) Minimum sum value of all UTXOs in " + CURRENCY_UNIT + "\n"
            "    }\n"
            "\nResult\n"
            "[                   (array of json object)\n"
            "  {\n"
            "    \"txid\" : \"txid\",          (string) the transaction id \n"
            "    \"vout\" : n,               (numeric) the vout value\n"
            "    \"address\" : \"address\",    (string) the bitcoin address\n"
            "    \"label\" : \"label\",        (string) The associated label, or \"\" for the default label\n"
            "    \"scriptPubKey\" : \"key\",   (string) the script key\n"
            "    \"amount\" : x.xxx,         (numeric) the transaction output amount in " + CURRENCY_UNIT + "\n"
            "    \"confirmations\" : n,      (numeric) The number of confirmations\n"
            "    \"redeemScript\" : n        (string) The redeemScript if scriptPubKey is P2SH\n"
            "    \"spendable\" : xxx,        (bool) Whether we have the private keys to spend this output\n"
            "    \"solvable\" : xxx,         (bool) Whether we know how to spend this output, ignoring the lack of keys\n"
            "    \"safe\" : xxx              (bool) Whether this output is considered safe to spend. Unconfirmed transactions\n"
            "                              from outside keys and unconfirmed replacement transactions are considered unsafe\n"
            "                              and are not eligible for spending by fundrawtransaction and sendtoaddress.\n"
            "  }\n"
            "  ,...\n"
            "]\n"
            "\nExamples\n"
            + HelpExampleCli("listunspent", "")
            + HelpExampleCli("listunspent", "6 9999999 \"[\\\"1PGFqEzfmQch1gKD3ra4k18PNj3tTUUSqg\\\",\\\"1LtvqCaApEdUGFkpKMM4MstjcaL4dKg8SP\\\"]\"")
            + HelpExampleRpc("listunspent", "6, 9999999 \"[\\\"1PGFqEzfmQch1gKD3ra4k18PNj3tTUUSqg\\\",\\\"1LtvqCaApEdUGFkpKMM4MstjcaL4dKg8SP\\\"]\"")
            + HelpExampleCli("listunspent", "6 9999999 '[]' true '{ \"minimumAmount\": 0.005 }'")
            + HelpExampleRpc("listunspent", "6, 9999999, [] , true, { \"minimumAmount\": 0.005 } ")