Reverse Proxy Configuration in ownCloud is old and missing examples

[voroyam]

WHAT Needs to be Documented?

 * Define list of trusted proxy servers
 *
 * If you configure these also consider setting `forwarded_for_headers` which
 * otherwise defaults to `HTTP_X_FORWARDED_FOR` (the `X-Forwarded-For` header).
 */
'trusted_proxies' => [
	'203.0.113.45',
	'198.51.100.128'
  ],

 * Define `forwarded_for_headers`
 * Headers that should be trusted as client IP address in combination with
 * `trusted_proxies`. If the HTTP header looks like 'X-Forwarded-For', then use
 * 'HTTP_X_FORWARDED_FOR' here.
 *
 * If set incorrectly, a client can spoof their IP address as visible to
 * ownCloud, bypassing access controls and making logs useless!
 *
 * If not set, defaults to 'HTTP_X_FORWARDED_FOR'.
 */
'forwarded_for_headers' => [
	'HTTP_X_FORWARDED',
	'HTTP_FORWARDED_FOR'
  ],

Extra things to remember:

• the headers may be different depending on your proxy software.
• need to check if the timeouts defined in apache conf are the same as in the reverse proxy config.

Timeout 300
KeepAlive On
MaxKeepAliveRequests 200
KeepAliveTimeout 3

WHERE Does This Need To Be Documented (Link)?

https://doc.owncloud.com/server/next/admin_manual/configuration/server/reverse_proxy_configuration.html

WHY Should This Change Be Made?

because right now it's just text, hard to read text.

(Optional) What Type Of Content Change Is This?

• [x] New Content Addition
• [ ] Old Content Deprecation
• [ ] Existing Content Simplification
• [ ] Bug Fix to Existing Content

(Optional) Which Manual Does This Relate To?

• [x] Admin Manual
• [ ] Developer Manual
• [ ] User Manual
• [ ] Android
• [ ] iOS
• [ ] Branded Clients
• [ ] Desktop Client
• [ ] Other