feat(env): rename vpn port forwarding variables

- `VPN_PORT_FORWARDING_STATUS_FILE`
- `VPN_PORT_FORWARDING`
- Deprecate PIA specific variables for VPN port forwarding

Dockerfile

@@ -108,8 +108,8 @@ ENV VPN_SERVICE_PROVIDER=pia \
     OWNED_ONLY=no \
     # # Private Internet Access only:
     PRIVATE_INTERNET_ACCESS_OPENVPN_ENCRYPTION_PRESET= \
-    PRIVATE_INTERNET_ACCESS_VPN_PORT_FORWARDING=off \
-    PRIVATE_INTERNET_ACCESS_VPN_PORT_FORWARDING_STATUS_FILE="/tmp/gluetun/forwarded_port" \
+    VPN_PORT_FORWARDING=off \
+    VPN_PORT_FORWARDING_STATUS_FILE="/tmp/gluetun/forwarded_port" \
     # # Cyberghost only:
     OPENVPN_CERT= \
     OPENVPN_KEY= \

internal/configuration/sources/env/portforward.go

@@ -9,6 +9,7 @@ import (
 func (s *Source) readPortForward() (
 	portForwarding settings.PortForwarding, err error) {
 	key, _ := s.getEnvWithRetro(
+		"VPN_PORT_FORWARDING",
 		"PRIVATE_INTERNET_ACCESS_VPN_PORT_FORWARDING",
 		"PORT_FORWARDING")
 	portForwarding.Enabled, err = envToBoolPtr(key)
@@ -17,6 +18,7 @@ func (s *Source) readPortForward() (
 	}
 
 	_, value := s.getEnvWithRetro(
+		"VPN_PORT_FORWARDING_STATUS_FILE",
 		"PRIVATE_INTERNET_ACCESS_VPN_PORT_FORWARDING_STATUS_FILE",
 		"PORT_FORWARDING_STATUS_FILE")
 	if value != "" {

maintenance.md

@@ -27,7 +27,7 @@
   - `UNBLOCK`
   - `PROTOCOL`
   - `PIA_ENCRYPTION`
-  - `PORT_FORWARDING`
+  - `PORT_FORWARDING`, `PRIVATE_INTERNET_ACCESS_VPN_PORT_FORWARDING`
   - `WIREGUARD_PORT`
   - `REGION` for PIA, Cyberghost
   - `WIREGUARD_ADDRESS`
@@ -40,7 +40,7 @@
   - `SERVER_NUMBER`
   - `SERVER_NAME`
   - `PUBLICIP_FILE`
-  - `PORT_FORWARDING_STATUS_FILE`
+  - `PORT_FORWARDING_STATUS_FILE`, `PRIVATE_INTERNET_ACCESS_VPN_PORT_FORWARDING_STATUS_FILE`
 - Updater servers version reset to 1
 - Reset HTTP server version to v1 and remove older ones
 - Change to compulsory