Pull Req for multi VRF support

[ssasso]

Right now it seems the BGP role does not support multiple VRF.
In addition to that, the VRF part is very limited.

With this PR I'm trying to address multiple VRF for the BGP configuration, and at the same time add more parameters.

[ssasso]

Examples:

dellos_bgp:
  vrfs:
  - name: "AAA"
    ipv4_network:
      - state: present
        address: "10.0.0.0/24"
      - state: present
        address: "192.168.0.0/24"
    address_family:
    - type: ipv4
      state: present
      redistribute:
      - route_type: l2vpn
        state: present
    neighbor:
    - type: peergroup
      name: "xlink"
      state: present
      bfd: "true"
    - type: peergroup
      name: "test_deflt"
      password: Banana44
      state: present
      bfd: true
      subnet: "10.20.30.0/24"
      address_family:
      - type: ipv4
        state: present
        default_originate: true
    - type: ipv4
      description: "Crosslink"
      interface: vlan2601
      peergroup: "xlink"
      peergroup_type: ibgp
      admin: up
      state: present
    - type: ipv4
      description: Test
      admin: down
      state: present
      ip: 10.44.44.3
      address_family:
      - type: ipv4
        state: present
        activate: true
        soft_reconf: true
        next_hop_self: true

[skg-net]

@ssasso Thanks for the PR. Our team is currently testing the PR. Once qualified we will merge it.