Dynamic modules: auto/module script. This script simplifies configuration of additional modules, including 3rd party ones. The script is extensible, and will be used to introduce dynamic linking of modules in upcoming changes. 3rd party module config scripts are called with ngx_module_link preset to "ADDON" - this allows config scripts to call auto/module without ngx_module_link explicitly defined, as well as testing if new interface is in place if compatibility with older nginx versions is desired. In collaboration with Ruslan Ermilov.