Move FAQ from wiki to git to allow contributions (#611)

Signed-off-by: Stanislas Lange <angristan@pm.me>

FAQ.md

@@ -0,0 +1,47 @@
+# FAQ
+
+**Q:** The script has been updated since I installed OpenVPN. How do I update?
+
+**A:** You can't. Managing updates and new features from the script would require way too much work. Your only solution is to uninstall OpenVPN and reinstall with the updated script.
+
+You can, of course, it's even recommended, update the `openvpn` package with your package manager.
+
+---
+
+**Q:** How do I check for DNS leaks?
+
+**A:** Go to [dnsleaktest.com](https://dnsleaktest.com/) or [ipleak.net](https://ipleak.net/) with your browser. Only your server's IP should show up.
+
+---
+
+**Q:** Can I use an OpenVPN 2.3 client?
+
+**A:** Yes. I really recommend using an up-to-date client, but if you really need it, choose the following options:
+
+- No compression or LZ0
+- RSA certificate
+- DH Key
+- AES CBC
+- tls-auth
+
+If your client is <2.3.3, remove `tls-version-min 1.2` from your `/etc/openvpn/server.conf` and `.ovpn` files.
+
+---
+
+**Q:** IPv6 is not working on my Hetzner VM
+
+**A:** This an issue on their side. See https://angristan.xyz/fix-ipv6-hetzner-cloud/
+
+---
+
+**Q:** DNS is not working on my Linux client
+
+**A:** Make sure the `resolvconf` package is installed. If it does not solve the issue, look at https://wiki.archlinux.org/index.php/OpenVPN#Update_systemd-resolved_script
+
+---
+
+**Q:** How to setup openVPN in a LXC container? (f.e. Proxmox)
+
+**A:** See https://github.com/Nyr/openvpn-install/wiki/How-to-setup-openVPN-in-a-LXC-container-(f.e.-Proxmox)
+
+---