bgpd: Show the real prefix for `show bgp detail`

bgpd: Show the real prefix for `show bgp detail`

Absolutely not possible to read the output and even distinguish the prefix
we are looking for.

Before:

```
donatas-pc# show ip bgp detail
BGP table version is 12, local router ID is 192.168.10.17, vrf id 0
Default local pref 100, local AS 65002
Status codes:  s suppressed, d damped, h history, * valid, > best, = multipath,
               i internal, r RIB-failure, S Stale, R Removed
Nexthop codes: @NNN nexthop's vrf id, < announce-nh-self
Origin codes:  i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

    Network          Next Hop            Metric LocPrf Weight Path
  65001
    2a02:4780:abc::2 from 2a02:4780:abc::2 (200.200.200.202)
    (fe80::a00:27ff:fe5e:d19e) (used)
      Origin incomplete, metric 0, valid, external, multipath
      Last update: Tue Dec 13 22:53:16 2022
  65001
    192.168.10.124 from 192.168.10.124 (200.200.200.202)
      Origin incomplete, metric 0, valid, external, otc 65001, multipath, best (Neighbor IP)
      Last update: Tue Dec 13 22:53:16 2022
  65001
    2a02:4780:abc::2 from 2a02:4780:abc::2 (200.200.200.202)
    (fe80::a00:27ff:fe5e:d19e) (used)
      Origin IGP, metric 0, valid, external, multipath
      Last update: Tue Dec 13 22:53:16 2022
  65001
    192.168.10.124 from 192.168.10.124 (200.200.200.202)
      Origin IGP, metric 0, valid, external, otc 65001, multipath, best (Neighbor IP)
      Last update: Tue Dec 13 22:53:16 2022
```

After:

```
donatas-pc# show ip bgp detail
BGP table version is 12, local router ID is 192.168.10.17, vrf id 0
Default local pref 100, local AS 65002
BGP routing table entry for 10.0.2.0/24, version 1
Paths: (2 available, best #2, table default)
  Advertised to non peer-group peers:
  2a02:4780:abc::2
  65001
    2a02:4780:abc::2 from 2a02:4780:abc::2 (200.200.200.202)
    (fe80::a00:27ff:fe5e:d19e) (used)
      Origin incomplete, metric 0, valid, external, multipath
      Last update: Tue Dec 13 22:47:16 2022
BGP routing table entry for 10.0.2.0/24, version 1
Paths: (2 available, best #2, table default)
  Advertised to non peer-group peers:
  2a02:4780:abc::2
  65001
    192.168.10.124 from 192.168.10.124 (200.200.200.202)
      Origin incomplete, metric 0, valid, external, otc 65001, multipath, best (Neighbor IP)
      Last update: Tue Dec 13 22:47:16 2022
BGP routing table entry for 10.10.100.0/24, version 2
Paths: (2 available, best #2, table default)
  Advertised to non peer-group peers:
  2a02:4780:abc::2
  65001
    2a02:4780:abc::2 from 2a02:4780:abc::2 (200.200.200.202)
    (fe80::a00:27ff:fe5e:d19e) (used)
      Origin IGP, metric 0, valid, external, multipath
      Last update: Tue Dec 13 22:47:16 2022
```

Signed-off-by: Donatas Abraitis <donatas@opensourcerouting.org>