Add support for non-MLAG Port-Channels

[blemmenes]

If a server has a port-channel defined, but the connections are on only one leaf MLAG is not needed.

This PR handles that case both for single link port-channels and multiples as shown below.

  server01:
    rack: RackA
    adapters:
      - server_ports: [ Eth1, Eth2 ]
        switch_ports: [ Ethernet11, Ethernet11 ]
        switches: [ DC1-SVC3A, DC1-SVC3A ]
        profile: TENANT_A_B
        port_channel:
          state: present
          description: PortChanne1
          mode: active

[carlbuchmann]

@blemmenes, thank you for your suggestion, looks good and will also update examples repo!