modulesync 5.4.0

Allow specification of up to three-level subdirectory hierarchy for
both [client_body_temp_path](https://nginx.org/en/docs/http/ngx_http_core_module.html#client_body_temp_path)
and [proxy_temp_path](https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_temp_path) options

This allows for the existing string option to specify just the path as
it works now, and for an alternate type as an array with the first
element as the path, and the up to 3 additional integers for each level

- Updated docs
- Updated tests

Rubocop fix

Apply suggestions from code review

Co-authored-by: Ewoud Kohl van Wijngaarden <ewoud@kohlvanwijngaarden.nl>

Rubocop suggested fix

Enable subdirectory hierarchy for client_body and proxy temp paths

https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_cache_background_update
Signed-off-by: Christian Ruppert <idl0r@qasl.de>

Add support for proxy_cache_background_update

https://nginx.org/en/docs/http/ngx_http_proxy_module.html#proxy_cache_convert_head

Signed-off-by: Christian Ruppert <idl0r@qasl.de>

Add support for proxy_cache_convert_head

allow setting of map_hash_bucket_size and map_hash_max_size

Release 4.3.0