Improve Haveno's censorship resistance

[erciccione]

These are not priorities at the moment, but need to be done before going live.

• [ ] Mirror repositories on gitlab and self hosted git
• [x] https://github.com/haveno-dex/haveno-meta/issues/2
• [ ] Domains
• [ ] PGP signed canary
• [ ] Backup servers to privacy-aware countries

Suggestions are welcome.