v0.6.0 Provider reports for probe bans

Adds provider reports to GitHub builds. Full list in CHANGELOG.md.

• GitHub build only: each probe ban and probe would-be ban on the Bans tab gets a Provider report button. It looks up the abuse contact of the address's network through RIPEstat and shows a ready-to-send plain-text report, which you copy or open in your own mail app. The plugin never mails the provider, and the lookup runs only when you press the button.
• No change to the wordpress.org build.