Basic ISIS Server part #1 (#173)

config/isis.go

config/isis_test.go

protocols/device/device.go

protocols/device/server.go

protocols/device/server_darwin.go

protocols/device/server_mock.go

protocols/device/server_test.go

protocols/isis/packet/isis.go

protocols/isis/packet/tlv_protocols_supported.go

protocols/isis/server/device.go

protocols/isis/server/device_test.go

protocols/isis/server/devices.go

protocols/isis/server/devices_test.go

protocols/isis/server/lsdb.go

protocols/isis/server/lsdb_test.go

protocols/isis/server/neighbor.go

protocols/isis/server/neighbors.go

protocols/isis/server/server.go

protocols/isis/server/server_test.go

protocols/isis/server/sys.go