[syncthing] Improve configuration

Use environment variables instead of CLI arguments where possible and
properly separate config and database/state directories.

syncthing/Dockerfile

@@ -4,6 +4,13 @@ FROM $BUILD_FROM
 RUN apk add --no-cache --repository=https://dl-cdn.alpinelinux.org/alpine/edge/community \
 		"syncthing=1.25.0-r1"
 
+COPY root /
+
+ENV STCONFDIR=/config \
+    STDATADIR=/data \
+    STNODEFAULTFOLDER=1 \
+		STNORESTART=1 \
+    STNOUPGRADE=1
+
 ENTRYPOINT [ "/init" ]
 CMD []
-COPY root /

syncthing/root/etc/s6-overlay/s6-rc.d/syncthing/run

@@ -2,19 +2,17 @@
 # shellcheck shell=bash
 set -e
 
-export STNOUPGRADE=1
-
-bashio::log.info 'Setup config'
-mkdir -p /data/config
+bashio::log.info 'Intializing Syncthing'
 
 ip=$(ifconfig | grep "inet " | grep -Fv 127.0.0.1 | awk '{sub("addr:",""); print $2}' | head -n 1)
 
 if [ -z "$ip" ]
 then
-      ip=0.0.0.0
+  ip=0.0.0.0
+  bashio::log.info "Couldn't detect IP address. Falling back to: $ip"
+else
+  bashio::log.info "Detected IP address: $ip"
 fi
 
-bashio::log.info "Detected IP Address: $ip"
-
-bashio::log.info 'Start syncthing'
-syncthing --no-browser --no-restart --home=/data/config --gui-address="$ip:8384"
+bashio::log.info 'Starting Syncthing'
+syncthing --gui-address="$ip:8384" --no-browser