* node: expose config in service context
* eth: integrate p2p/dnsdisc
* cmd/geth: add some DNS flags
* eth: remove DNS URLs
* cmd/utils: configure DNS names for testnets
* params: update DNS URLs
* cmd/geth: configure mainnet DNS
* cmd/utils: rename DNS flag and fix flag processing
* cmd/utils: remove debug print
* node: fix test
* node: close AccountsManager in new Close method
* p2p/simulations, p2p/simulations/adapters: handle node close on shutdown
* node: move node ephemeralKeystore cleanup to stop method
* node: call Stop in Node.Close method
* cmd/geth: close node.Node created with makeFullNode in cli commands
* node: close Node instances in tests
* cmd/geth, node: minor code style fixes
* cmd, console, miner, mobile: proper node Close() termination