Solo mining: added job timeout (default is 15 seconds)

It's important to update jobs frequently to get new transactions into the block template. See https://rucknium.me/posts/monero-pool-transaction-delay/ for more details.

src/core/config/Config_platform.h

@@ -50,6 +50,7 @@ static const option options[] = {
     { "http-no-restricted",    0, nullptr, IConfig::HttpRestrictedKey     },
     { "daemon",                0, nullptr, IConfig::DaemonKey             },
     { "daemon-poll-interval",  1, nullptr, IConfig::DaemonPollKey         },
+    { "daemon-job-timeout",    1, nullptr, IConfig::DaemonJobTimeoutKey   },
     { "self-select",           1, nullptr, IConfig::SelfSelectKey         },
     { "submit-to-origin",      0, nullptr, IConfig::SubmitToOriginKey     },
     { "daemon-zmq-port",       1, nullptr, IConfig::DaemonZMQPortKey      },