wg-installer: add wg-installer

This tool can be used to automatically create wireguard tunnels. Using
rpcd a new wireguard interface is created on the server where the client
can connect to.

Wiregurad server automatically installs a user and associated ACL to use
the wireguard-installer-server features. The user is called wginstaller
and so is the password.

Get Usage:
  wg-client-installer get_usage --ip 127.0.0.1 --user wginstaller
	--password wginstaller

Register Interface:
  wg-client-installer register --ip 127.0.0.1 --user wginstaller
         --password wginstaller --bandwidth 10 --mtu 1400

Signed-off-by: Nick Hainke <vincent@systemli.org>

net/wg-installer/wg-server/config/wginstaller.json

@@ -0,0 +1,19 @@
+{
+    "wginstaller": {
+        "description": "WireGuard Installer",
+        "read": {
+            "ubus": {
+                    "wginstaller": [ "*" ],
+                    "session": [
+                        "access",
+                        "login"
+                ]
+            }
+        },
+        "write": {
+            "ubus": {
+                    "wginstaller": [ "*" ]
+            }
+        }
+    }
+}

net/wg-installer/wg-server/config/wgserver.conf

@@ -0,0 +1,6 @@
+config server
+    option port_start '51820'
+    option port_end '52820'
+    option base_prefix '2002::/64'
+    option wg_key '/root/wg.key'
+    option wg_pub '/root/wg.pub'