chore(docs): use gh action to build docs (#8097)

# Which Problems Are Solved

This allows us to build multiple docs in parallel and only runs when
docs/proto are changed.

# Additional Changes

- [ ] Change "required" in GitHub from Vercel to the docs flow

---------

Co-authored-by: Livio Spring <livio.a@gmail.com>

docs/nginx.conf

@@ -1,56 +0,0 @@
-events { 
-  worker_connections  1024;  ## Default: 1024 
-} 
- 
-http { 
-
-    include /etc/nginx/mime.types; 
- 
-     server { 
-        
-        listen 8080;
-
-        location / { 
-          return 301 /docs;
-        } 
- 
-        location /docs { 
-            alias /usr/share/nginx/html;
-            index /docs/index.html;
-            try_files $uri $uri/ /docs/index.html?q=$query_string; 
-        } 
-
-        location = /docs/proxy/js/script.js {
-            proxy_pass https://plausible.io/js/script.js;
-            proxy_set_header Host plausible.io;
-        }
-
-        location = /docs/proxy/api/event {
-            proxy_pass https://plausible.io/api/event;
-            proxy_set_header Host plausible.io;
-            proxy_buffering on;
-            proxy_http_version 1.1;
-
-            proxy_set_header X-Forwarded-For   $proxy_add_x_forwarded_for;
-            proxy_set_header X-Forwarded-Proto $scheme;
-            proxy_set_header X-Forwarded-Host  $host;
-        }
-    } 
- 
-    ## enable gzip compression 
-    gzip on; 
-    gzip_vary on; 
-    gzip_min_length 256; 
-    gzip_proxied any; 
- 
-    gzip_types 
-      ## text/html is always compressed : https://nginx.org/en/docs/http/ngx_http_gzip_module.html 
-      text/plain 
-      text/css 
-      text/javascript 
-      application/javascript 
-      application/x-javascript 
-      application/xml 
-      application/json 
-      application/ld+json; 
-}