Add support for QLatin1StringMatcher to search inside a String/QStringView haystack

The QLatin1StringMatcher can search for a QLatin1StringView needle inside a QLatin1StringView haystack. It is a low hanging fruit to add support to search inside a QStringView or QString haystack as well. The building of the skip table remains unchanged, only two new trivial indexIn functions and possibly a tweaked Boyer-Moore search function needs to be added.

The advantage is that we no longer have to convert the needle into a QString which is needed to use the similar QStringMatcher.

If we add support for this in the constexpr QStaticLatin1StringMatcher as well, we can search through a QString/QStringView with a compile time computed skip table. A constexpr QString searcher does not exist, so this will be a major benefit.