Add OpenWISP to Network configuration management tools

[kosli]

As mentioned in #439

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• Your additions are Free software
• Software your are submitting is not your own, unless you have a healthy ecosystem with a few contributors (which aren't your sock puppet accounts).
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Why it is awesome

With OpenWISP it is easily possible to manage 100s of routers & access points from a central web gui with many additional useful futures. Just amazing!

[nodiscc]

Looks nice.

• Have you used it? For how long?
• Is this in a personal or professional setup?
• How many devices do you manage with it?
• Biggest pros/cons compared to other solutions?
• Any other comments about your use case, things you've found excellent, limitations you've encountered... ?