QString is UTF-16, thus QString::size returns the number of UTF-16 code
units. Thus, we would fail to perform, for example:
ak_string_from_qstring(QString("😀"));
Which is 2 UTF-16 code units, but 4 UTF-8 code units.
There's no need for 2 overloads for String and DeprecatedString, we can
just use a StringView. This also avoids some cases of needlessly
allocating a DeprecatedString from a StringView when calling this
method.
This will help a lot with developing chromes for different UI frameworks
where we can see which helper classes and processes are really using Qt
vs just using it to get at helper data.
As a bonus, remove Qt dependency from WebDriver.
