Description of problem:

General Requirement (User Story) 
As a user, I can use the policy routing, so that I can forward the packet based on other criteria except the destination address in the packet. (e.g. Source Routing)

Acceptance Criteria: 
- Given a Linux system, 
  when a user applies the following playbook,
  ```
    network_connections:
      - name: eth0
        state: up
        type: ethernet
        ip:
          dhcp4: no
          address:
           - 198.51.100.3/26
          route:
           - network: 198.51.100.128
             prefix: 26
             gateway: 198.51.100.1
             metric: 2
  +	     table: 30400  
           - network: 198.51.100.64
             prefix: 26
             gateway: 198.51.100.6
             metric: 4
  +	     table: 30200
  ```
  then `ip route` will show "198.51.100.128/26 via 198.51.100.1 dev eth0 metric 2 table 30400" and "198.51.100.64/26 via 198.51.100.6 dev eth0 metric 4 table 30200"

- Given a Linux system, 
  when a user applies the following playbook,
  ```
  hosts: all
  tasks:
    - name: Add a new routing table
      lineinfile:
        path: /etc/iproute2/rt_tables
        line: "200 custom"

    - name: Set up the network connection
      import_role:
        name: linux-system-roles.network
      vars:
        network_connections:
          - name: eth0
            state: up
            type: ethernet
            ip:
              dhcp4: no
              address:
               - 198.51.100.3/26
              route:
               - network: 198.51.100.128
                 prefix: 26
                 gateway: 198.51.100.1
                 metric: 2
  +	         table: custom 
               - network: 198.51.100.64
                 prefix: 26
                 gateway: 198.51.100.6
                 metric: 4
  +	         table: custom
  ```
  then `ip route` will show "198.51.100.128/26 via 198.51.100.1 dev eth0 metric 2 table custom" and "198.51.100.64/26 via 198.51.100.6 dev eth0 metric 4 table custom"


Notice that the Network role will support both the named and numeric tables. 

How to test:
`ip route` will list the routes and the associated routing tables.