Add hsts snippet

Caddyfile

@@ -24,6 +24,10 @@
 }
 
 (hsts) {
+    header Strict-Transport-Security max-age=31536000
+}
+
+(matrix-well-known) {
     handle_path /.well-known/matrix/* {
         header Access-Control-Allow-Origin "*"
         header Access-Control-Allow-Methods "GET, POST, PUT, DELETE, OPTIONS"