Prompt user to accept configuration from a web page

[rodolfomiranda]

As we discussed today, we will change a bit the flow when onboarding:

• the normal popup in a web page will be shown to head the user to click on the action button
• the config page will be shown with vendor URL and a message telling the user to accept or deny it. Also shown that the config came from the web page

[HunnySajid]

closing as it is merged with https://github.com/WebOfTrust/signify-browser-extension/pull/133