There should be a (class like) QStringTokenizer for QByteArray

There are instances where we need to split a QByteArray on a separator in the Qt code base; and most likely also in user code (searching for QByteArray::split invocations in Qt itself finds plenty).

With QByteArrayView, we have the necessary view class to support this.
Note that QStringTokenizer takes a case-sensitivity parameter which does not make sense for QByteArray (which has no concept of encoding).