readme improvements and multiple bugfixes

• fixed a bunch of typos
• fixed wrong output in various locations
• added keepalive to WireGuard for compatibility with some firewalls
• cleared a bug where OpenVPN wouldn't connect without PF
• forced locale to avoid curl bugs
• added backwards compatibility for Ubuntu 18.04
• added multiple distributions to the README
• added delay to allow WireGuard to fully connect before getting PF
• made OpenVPN credentials readable only by root
• fixed bug that appeared when IPv6 was disabled via kernel params
• added 3rd party repos to the readme