Update gitea download and switch to xz files

XZ files are downloaded
Change that any grep is replaced by jq command, and sed for " replace

Add systemd service files as samples

download.sh

@@ -6,8 +6,8 @@ BASE_FOLDER=$(dirname "$(readlink -f "$0")")"/";
 
 download_file=$(curl -s https://api.github.com/repos/go-gitea/gitea/releases/latest |\
 	jq ".assets[].browser_download_url" |\
-	cut -d '"' -f 4 |\
-	grep "${arch}$");
+	sed -e 's/"//g' |\
+	grep "${arch}.xz$");
 
 version=$(echo "${download_file}" | cut -d "/" -f 8);
 file=$(echo "${download_file}" | cut -d "/" -f 9);