Add an exit survey when the plugin is deactivated

[JuanchoPestana]

Fixes #2374

Changes proposed in this Pull Request

• WORK IN PROGRESS - Adds exit survey when plugin is deactivated.

[JuanchoPestana]

Hey @donnapep!

This PR should serve as a starting point for the exit survey. If you'll like me to handle it in a different way, let me know and I'll gladly modify it! If this approach works for you, let me know all the details (URL, data to send, formatting, etc) so that I can continue working on it!

The Travis Build is failing because of an error related to onboarding... Don't know what to do there to be honest!

[donnapep]

Hi @JuanchoPestana. Thanks for picking this up, although I'm not sure it's the best issue to work on right now as the details haven't been worked out yet. An issue can be considered ready to be worked on when it has a label of "[Status] Accepted".

Also, we know that we want to store these results in Automattic's Crowdsignal tool, so the implementation for this may actually end up being an integration of a survey that is build in Crowdsignal.

[JuanchoPestana]

Hey Donna! Ok great... Thanks for letting me know!