Add an example on how to configure SR-IOV to the nmcli examples man
page.

https://bugzilla.redhat.com/show_bug.cgi?id=1651979

Quick and easy way to get clean and parsable field values.

This improves the HTML rendering.

But it also causes a lot of non-resolvable linkends warning when rendering a
separate manual pages into roff/mman. The messages are harmless, but still
a bit ugly.

Add new Reload D-Bus command to reload NetworkManager configuration.

For now, this is like sending SIGHUP to the process. There are several
advantages here:

  - it is guarded via PolicyKit authentication while signals
    can only be sent by root.

  - the user can wait for the reload to be complete instead of sending
    an asynchronous signal. For now, we operation completes after
    nm_config_reload() returns, but later we could delay the response
    further until specific parts are fully reloaded.

  - SIGHUP reloads everything including re-reading configuration from
    disk while SIGUSR1 reloads just certain parts such as writing out DNS
    configuration anew.
    Now, the Reload command has a flags argument which is more granular
    in selecting parts which are to be reloaded. For example, via
    signals the user can:

      1) send SIGUSR1: this writes out the DNS configuration to
         resolv.conf and possibly reloads other parts without
         re-reading configuration and without restarting the DNS plugin.
      2) send SIGHUP: this reloads configuration from disk,
         writes out resolv.conf and restarts the DNS plugin.

    There is no way, to only restart the DNS plugin without also reloading
    everything else.

It's included from GFDL 1.1+ document; it should be GFDL too.