Add expose_php option with reduced precision

Description

As @krakjoe pointed out at https://github.com/php/php-src/pull/3335, the popular default configurations are decided by package managers and hosting providers, and the default already has expose_php enabled.

But, we also know that those same package managers and hosting providers feel their only option is to turn this off as a sort of security through obscurity. This in turn can deminish global statistics (e.g. W3 Techs).

Perhaps we could offer a middleground that would appeal to some of the package managers (e.g. Debian, Fedora), and major hosting providers to no longer turn it off completely. For example:

X-Powered-By: PHP/8.2.9

… could be reduced to:

X-Powered-By: PHP

One could instead consider preserving major or major+minor version. But, I think an option that controls simply whether the version is obscured is more likely to receive broad adoption, and keeps the API simpler to maintain and to consume (also crawlers interpreting and aggregating this information).

/cc @Slamdunk @petk

Beginne damit, die bestehende expose_php-Konfiguration und den Antwortpfad nachzuverfolgen, der den X-Powered-By-Header erzeugt. Vergleiche das vorgeschlagene Verhalten mit reduzierter Präzision mit den aktuellen Fällen für aktiviert und deaktiviert und ermittle anschließend die relevanten Konfigurations- und Test-Einstiegspunkte. Als erledigt gilt die Aufgabe, wenn eine unterstützte Option den Header beibehalten kann, während ihre Version weggelassen wird.