re-move extra headers, no longer needed

see PrivateBin/docker-unit-alpine#18

nginx.conf

@@ -168,12 +168,6 @@ server {
 
     # HSTS (15768000 seconds = 6 months)
     add_header Strict-Transport-Security "max-age=15768000; includeSubDomains; preload";
-    add_header Cross-Origin-Embedder-Policy require-corp;
-    add_header Cross-Origin-Resource-Policy same-origin;
-    add_header Referrer-Policy no-referrer;
-    add_header X-Content-Type-Options nosniff;
-    add_header X-Frame-Options deny;
-    add_header X-XSS-Protection "1; mode=block";
 
     # proxy to demo site container
     location / {
@@ -186,12 +180,6 @@ server {
         proxy_pass  http://demo;
         proxy_cache privatebin;
         proxy_http_version 1.1;
-        proxy_hide_header Cross-Origin-Embedder-Policy;
-        proxy_hide_header Cross-Origin-Resource-Policy;
-        proxy_hide_header Referrer-Policy;
-        proxy_hide_header X-Content-Type-Options;
-        proxy_hide_header X-Frame-Options;
-        proxy_hide_header X-XSS-Protection;
         proxy_set_header Host $host;
         proxy_set_header X-Real-IP $remote_addr;
         proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;