"Nginx Config improvement" Fix

[marcel-wiechmann]

Within #519 you made changes based on #518. Now within the example configuration the Section "# Extend timeouts for long connections" is included twice.

Also you enable http2 by adjusting the "listen" directive which is outdated. You should simply add "http2 on;" (https://nginx.org/en/docs/http/ngx_http_v2_module.html)

[marcel-wiechmann]

Also other sections are included twice

[marcel-wiechmann]

That adjusting "listen" is outdated can be found here https://nginx.org/en/docs/http/ngx_http_core_module.html#listen