Close#23711, thanks to @ghnp5 !
Close #24612, thanks to @DanielGibson !
Major changes:
* the default value of nginx's client_max_body_size is too small, so put
a 512M here
* move `Resolving Error: 413 Request Entity Too Large` to a sub-section
of `Nginx` section
* make nginx use unescaped the URI and keep "%2F" as is when using
sub-path
* add details for General sub-path configuration
