Fix #244: Disable buffer for comments

[dellagustin]

Comments for an episode are sent back to the front end using chunked Transfer Enconding, but that that is not supported on HTTP/2 which is used by the reverse proxy (nginx).

At the moment nginx buffers the chunks before sending them to the browser, which breaks the way the chunks are processed.

With this commit, we use the header X-Accel-Buffering to disable this buffering, which worked in local testing.

We should still add a more clear chunk delimiter so that any other buffering or unknown edge case will not
break the comments function (increase robustness).

Co-authored-by: @ericpp

Fixes #244

[dellagustin]

Here is the code I used locally to test the web-ui and server behind nginx, based on ericpp@314519a from @ericpp .

./docker/ngingx.conf:

server {
    if ($host = www.podcastindex.org) {
        return 302 https://podcastindex.org$request_uri;
    }

    root /var/www/html;
    index index.html;
    server_name www.podcastindex.org podcastindex.org localhost;
    location / {
        proxy_set_header   X-Forwarded-For $remote_addr;
        proxy_set_header   Host $http_host;
        #proxy_pass         http://127.0.0.1:8000;       # First attempt to serve request as file, then
        proxy_pass         http://host.docker.internal:5001;       # First attempt to serve request as file, then
    }
    listen 80 default_server;
    add_header Strict-Transport-Security "max-age=31536000; includeSubDomains" always;
}

docker-compose.yml:

services:
  nginx:
    image: nginx
    ports: 
      - '8080:80'
    volumes:
      - ./docker/nginx.conf:/etc/nginx/conf.d/default.conf

With that, it can be tested with:

• yarn install
• npx webpack --env.file=development --mode development --devtool inline-source-map (the webpack dev server cannot be used for this test, the frontend will be served by the server)
• yarn start
• docker-compose up -d
• open http://localhost:8080/

I don't think this will work on linux. As far as I know, as it does not yet support host.docker.internal (at least not exactly in the same way - see docker/for-linux#264).
See