add requirements

data/radicale.md

@@ -1,6 +1,7 @@
 ---
 title: "radicale and nginx"
 tags: [ "data", "calendar" ]
+required: [ "nginx", "certbot" ]
 ---
 
 Check before you start:

data/soft_https.md

@@ -1,6 +1,7 @@
 ---
 title: "Soft Serve through https"
 tags: [ "data", "git server", "lfs" ]
+required: [ "git", "nginx" ]
 ---
 
 ## `http` Setup