NGINX One: Document NGINX config file limits

[CVanF5]

Is your feature request related to a problem? Please describe

N1CC has limits on NGINX config file sizes. Both for individual files and total cumulative limits for multiple files. These limits don't appear to be documented.

Describe the solution you'd like

A note perhaps here: https://docs.nginx.com/nginx-one/how-to/nginx-configs/add-instance/ on those limits so the end user is aware.

Describe alternatives you've considered

A separate tasks exists for the NGINX Agent to log such errors and make it clear to the user that the limits have been reached.