Update install script to accept proxy

scripts/install.sh

@@ -4,12 +4,17 @@
 ### of `scaricatore`.
 
 PROJECT_ROOT=$1
+PROXY=$2
 
 if [ -z ${PROJECT_ROOT+x} ]; then
-    echo "error no project_root set"
+    echo "ERROR: No PROJECT_ROOT set (first argument to ${0})"
     exit 1
 fi
 
+if [ -z ${PROXY+x} ]; then
+    echo "INFO: no proxy given"
+fi
+
 mkdir -p "${PROJECT_ROOT}"
 cd "${PROJECT_ROOT}" || exit 1
 
@@ -25,3 +30,4 @@ rm build.tar.gz
 npm ci
 npm run download-yt-dlp
 echo "YTDLP_PATH=$(readlink -f yt-dlp)" >>.env
+echo "HTTPS_PROXY=${PROXY}" >>.env