Docker improvements

- Modify onionr.sh to parse env and supply args to run-onionr-node.py
- Run onionr by default rather than bash
- Run as unprivileged user by default instead of root
- Use /app for all code
- Specify python 3.7 (3.8 fails to build cffi)
- Use apt-get rather than apt (apt's CLI is not stable)
- Slight reformatting and consolidation

onionr.sh

@@ -2,5 +2,22 @@
 ORIG_ONIONR_RUN_DIR=`pwd`
 export ORIG_ONIONR_RUN_DIR
 cd "$(dirname "$0")"
-cd src
-./__init__.py "$@"
+
+[[ -n "$USE_TOR" ]] || USE_TOR=1
+[[ -n "$PORT" ]] || PORT=8080
+[[ -n "$KEEP_LOG" ]] || KEEP_LOG=0
+[[ -n "$STORE_PLAINTEXT" ]] || STORE_PLAINTEXT=1
+
+PRIVKEY_OPT=""
+[[ -f "privkey.key" ]] && PRIVKEY_OPT="--private-key privkey.key"
+
+python run-onionr-node.py \
+	--open-ui 0 \
+	--onboarding 0 \
+	--bind-address 0.0.0.0 \
+	--port $PORT \
+	--use-tor $USE_TOR \
+	--keep-log-on-exit $KEEP_LOG \
+	--store-plaintext $STORE_PLAINTEXT \
+	$PRIVKEY_OPT \
+	"$@"