We sometimes had one and mostly had two capture groups. Now we always have two capture groups and thus can always use $2 for the redirect target.

Fixes #6144

Skip possible IO extensive operations for vhostalias creation on "web" document root

trimmed the code since it seems to be enough to provide TLS 1.3 when Nginx was linked against OpenSSL 1.1.1 at build time

- removed master_directive_snippet code that was (in 2016) accidently backported from master but never used

- move all updates to onAfterUpdate
- remove server parts that are not needed

- fixed several issues
- fixed variable typos
- coding styles

nginx_plugin: delete statistic generator configuration files if they have been changed to something else