Add hide_blank to connection results on proxy settings

[chris1984]

Notice in my output we have HTTP Proxy and Ignore proxy nil but we still show the fields, we should hide them if the value in the DB is nil

[vagrant@hammer hammer-cli-foreman-virt-who-configure]$ hammer virt-who-config info --id 3
General information:
    Id:                 3
    Name:               Kubevirt
    Hypervisor type:    kubevirt
    Configuration file: /root/test
    Status:             No Report Yet
Schedule:
    Interval:       every 2 hours
    Last Report At:
Connection:
    Satellite server:     devel.katello.lan
    Hypervisor ID:        hostname
    Filtering:            Unlimited
    Filter host parents:
    Exclude host parents:
    Debug mode:           no
    Ignore proxy:
HTTP Proxy: