adapt print_result processor to nornir 3.0.0

[dbarrosop]

Relates to #486 and #504

Adapt plugin to nornir 3.0.0.

For reference look at https://github.com/nornir-automation/nornir_napalm.

Don't forget to add details to the plugin repository. You can do so by adding it here

If you have any questions don't hesitate to ask.

[dbarrosop]

For simple/standalone plugins that don't require external dependencies I was thinking that a nornir_utils repo might be enough, happy to discuss ideas.

[ogenstad]

The sad think in this case is that even the simple print requires the colorama library. Perhaps that can be optional so that it prints without color if the library isn't installed.