mgadm should sort routes numerically

[taspelund]

When mgadm returns a RIB, the prefixes are sorted lexicographically, not numerically.
e.g.

root@oxz_switch0:~# mgadm bgp status imported 47
Static Routes
=============
Prefix     Nexthop       RIB Priority
0.0.0.0/0  198.51.103.1  1
0.0.0.0/0  198.51.103.9  1
BGP Routes
=============
Prefix        Nexthop       RIB Priority  Local Pref  Origin AS  Peer ID       MED   AS Path  Stale
0.0.0.0/0     198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.1.0/24    198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.10.0/24   198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.100.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.101.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.102.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.103.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.104.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.105.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.106.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.107.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.108.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.109.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.11.0/24   198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.110.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.111.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.112.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.113.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.114.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.115.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.116.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.117.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.118.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None
2.0.119.0/24  198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None     <<<<<<<
2.0.12.0/24   198.51.103.9  20            Some(20)    52         198.51.102.5  None  [52]     None      <<<<<<<

This could/should be improved to make things more legible to users, e.g. "119" shouldn't live between "11" and "12".