[production_web_proxying] add note about client_max_body_size to nginx

[duncdrum]

Where is the problem

By default nginx has client_max_body_size 1m;

What is the problem

not allowing larger sizes interfers with uploading .xar packages from development systems.
needs to be set twice in nginx.conf in http and server under location

Please provide the following

• exist-db version: 4.3.0
• documentation version: 4.0.3

[duncdrum]

@martindholmes looks like Apache has a similar problem tei-list

[martindholmes]

@duncdrum If I understand the documentation correctly (https://httpd.apache.org/docs/2.4/mod/core.html#limitrequestbody) the default in Apache is unlimited, but it's unlikely a cautious sysop would leave it that way.

[dizzzz]

should this really be documented in eXist-db documentation? probably not, only in 'generic terms' like

"your reverse proxy might have a limit on your HTTP request body, size URL etc. As a consequence it might nog be possible to upload large documents to eXist-db. Please consult the documentation for you reverse proxy for details."

Nothing more....

[duncdrum]

@dizzzz yes generic terms is what i had in mind with adding a note. but looking at the number of users (un-) knowingly struggling with this and blaming exist-db's storage capacities I think we should mention something in our docs.