[BACKLOG-1479]: Implement support for Carte parameters (threads and connections)

Implement necessary code changes to support configuring the following options for Carte:
acceptors, acceptQueueSize, lowResourcesMaxIdleTime.
lowResourcesConnections option is not supported by org.mortbay.jetty.bio.SocketConnector that is used in the current implementation of Carte web server so it's out of scope.
Also there are unit tests.