[jsk_fetch_startup] add network_status in fetch_bringup.launch

[knorth55]

launch jsk_network_tools/network_status.py in fetch_bringup.launch

cc. @708yamaguchi

[k-okada]

is this similar to #1253 ? @708yamaguchi

[knorth55]

@k-okada this is similar to #1253, but this node publish more detailed information about network.

$ rostopic echo /fetch1075/
/fetch1075/app_list                /fetch1075/eth1/transmit           /fetch1075/nonlocal/receive_mbps
/fetch1075/application/app_status  /fetch1075/eth1/transmit_kbps      /fetch1075/nonlocal/transmit
/fetch1075/eth0/receive            /fetch1075/eth1/transmit_mbps      /fetch1075/nonlocal/transmit_kbps
/fetch1075/eth0/receive_kbps       /fetch1075/lo/receive              /fetch1075/nonlocal/transmit_mbps
/fetch1075/eth0/receive_mbps       /fetch1075/lo/receive_kbps         /fetch1075/wlan0/receive
/fetch1075/eth0/transmit           /fetch1075/lo/receive_mbps         /fetch1075/wlan0/receive_kbps
/fetch1075/eth0/transmit_kbps      /fetch1075/lo/transmit             /fetch1075/wlan0/receive_mbps
/fetch1075/eth0/transmit_mbps      /fetch1075/lo/transmit_kbps        /fetch1075/wlan0/transmit
/fetch1075/eth1/receive            /fetch1075/lo/transmit_mbps        /fetch1075/wlan0/transmit_kbps
/fetch1075/eth1/receive_kbps       /fetch1075/nonlocal/receive        /fetch1075/wlan0/transmit_mbps
/fetch1075/eth1/receive_mbps       /fetch1075/nonlocal/receive_kbps

$ rostopic echo /fetch1075/wlan0/receive_kbps
data: 1259.0
---
data: 1216.0
---
data: 1188.0
---
data: 1118.0
---

$ rostopic echo /fetch1075/wlan0/transmit_kbps
data: 18570.0
---
data: 18520.0
---
data: 18572.0
---
data: 18623.0
---
data: 18620.0
---
data: 18296.0
---

[knorth55]

I also use these topics for influxdb logging.
https://github.com/knorth55/influxdb_store/blob/master/node_scripts/network_states_logger.py