[V2] Ping doesn't work

Created by: edvgui

Using the ping route will raise a 500 because we convert intervals from float with a point (e.g. 1.0) to float with a comma (e.g. 1,0) which causes ping to raise a warning:

root@subscriber-north-east:/home/user# ping -i 1,0 -c 4 7.2.138.2
ping: option argument contains garbage: ,0
ping: this will become fatal error in the future
PING 7.2.138.2 (7.2.138.2) 56(84) bytes of data.
64 bytes from 7.2.138.2: icmp_seq=1 ttl=64 time=16.2 ms
64 bytes from 7.2.138.2: icmp_seq=2 ttl=64 time=4.10 ms
64 bytes from 7.2.138.2: icmp_seq=3 ttl=64 time=4.12 ms
^C
--- 7.2.138.2 ping statistics ---
3 packets transmitted, 3 received, 0% packet loss, time 2003ms
rtt min/avg/max/mdev = 4.099/8.125/16.162/5.682 ms

This warning comes in stderr, which raises the InternalServerError: https://github.com/inmanta/nfv-test-api/blob/ee04d636b4929a5a670aa7303a3bed1199adaafd/src/nfv_test_api/v2/services/actions.py#L46