networkd: add support to configure IP Rule (#5725)

networkd: add support to configure IP Rule (#5725)

Routing Policy rule manipulates rules in the routing policy database control the
route selection algorithm.

This work supports to configure Rule
```
[RoutingPolicyRule]
TypeOfService=0x08
Table=7
From= 192.168.100.18

```

```
ip rule show
0:	from all lookup local
0:	from 192.168.100.18 tos 0x08 lookup 7
```

V2 changes:

1. Added logic to handle duplicate rules.
2. If rules are changed or deleted and networkd restarted
   then those are deleted when networkd restarts next time

V3:

1. Add parse_fwmark_fwmask