improve cache control response headers

"Cache-Control: public, no-cache" response header is ambiguous as public
means the response can be cached.
Change this to just "no-cache"

This should not have any effect but it's easier to understand like this

88-tar1090.conf

@@ -17,14 +17,14 @@ alias.url += (
 $HTTP["url"] =~ "^/INSTANCE/data/.*\.binCraft$" {
     compress.filetype = ()
     setenv.add-response-header += (
-        "Cache-Control" => "public, no-cache",
+        "Cache-Control" => "no-cache",
         "Content-Encoding" => "gzip",
         )
 }
 $HTTP["url"] =~ "^/INSTANCE/data/.*\.zst$" {
     compress.filetype = ()
     setenv.add-response-header += (
-        "Cache-Control" => "public, no-cache",
+        "Cache-Control" => "no-cache",
         )
 }
 $HTTP["url"] =~ "^/INSTANCE/chunks/chunk_.*gz$" {
@@ -45,25 +45,25 @@ $HTTP["url"] =~ "^/INSTANCE/chunks/current_.*gz$" {
 }
 $HTTP["url"] =~ "^/INSTANCE/chunks/978\.json$" {
     setenv.add-response-header += (
-        "Cache-Control" => "public, no-cache",
+        "Cache-Control" => "no-cache",
         )
 }
 $HTTP["url"] =~ "^/INSTANCE/data/aircraft\.json$" {
     setenv.add-response-header += (
-        "Cache-Control" => "public, no-cache",
+        "Cache-Control" => "no-cache",
         )
 }
 $HTTP["url"] =~ "^/INSTANCE/data/globe.*json$" {
     compress.filetype = ()
     setenv.add-response-header += (
-        "Cache-Control" => "public, no-cache",
+        "Cache-Control" => "no-cache",
         "Content-Encoding" => "gzip",
         )
 }
 $HTTP["url"] =~ "^/INSTANCE/data/traces/" {
     compress.filetype = ()
     setenv.add-response-header += (
-        "Cache-Control" => "public, no-cache",
+        "Cache-Control" => "no-cache",
         "Content-Encoding" => "gzip",
         )
 }

nginx.conf

@@ -3,35 +3,35 @@ location /INSTANCE/data/ {
   alias SOURCE_DIR/;
   gzip_static off;
   location ~ aircraft\.json$ {
-    add_header Cache-Control "public, no-cache";
+    add_header Cache-Control "no-cache";
     gzip on;
     gzip_static on;
   }
   location /INSTANCE/data/traces/ {
     location ~ trace_recent {
       gzip off;
-    add_header Cache-Control "public, no-cache";
+    add_header Cache-Control "no-cache";
       add_header Content-Encoding "gzip";
     }
     location ~ trace_full {
       gzip off;
-    add_header Cache-Control "public, no-cache";
+    add_header Cache-Control "no-cache";
       add_header Content-Encoding "gzip";
     }
   }
   location ~ globe_.*\.json$ {
     gzip off;
-    add_header Cache-Control "public, no-cache";
+    add_header Cache-Control "no-cache";
     add_header Content-Encoding "gzip";
   }
   location ~ .*\.binCraft$ {
     gzip off;
-    add_header Cache-Control "public, no-cache";
+    add_header Cache-Control "no-cache";
     add_header Content-Encoding "gzip";
   }
   location ~ .*\.zst$ {
     gzip off;
-    add_header Cache-Control "public, no-cache";
+    add_header Cache-Control "no-cache";
   }
 }
 
@@ -46,7 +46,7 @@ location /INSTANCE/globe_history/ {
 
   location ~ /acas/ {
     default_type text/plain;
-    add_header Cache-Control "public, no-cache";
+    add_header Cache-Control "no-cache";
 
     gzip_static on;
   }
@@ -85,7 +85,7 @@ location /INSTANCE/chunks/ {
   }
   location ~ .*\.json$ {
     gzip on;
-    add_header Cache-Control "public, no-cache";
+    add_header Cache-Control "no-cache";
   }
 }
 
@@ -108,12 +108,12 @@ location /INSTANCE {
 
   # exact matches
   location = /INSTANCE/config.js {
-    add_header Cache-Control "public, no-cache";
+    add_header Cache-Control "no-cache";
     gzip on;
     gzip_static on;
   }
   location = /INSTANCE/index.html {
-    add_header Cache-Control "public, no-cache";
+    add_header Cache-Control "no-cache";
     gzip on;
     gzip_static on;
   }