Add str_arg_char specializations for ATL/MFC and Qt strings

[rmisev]

Added support for ATL/MFC and Qt string input. To use them you need to include the header files listed in the table below instead of url.h:

Library	Supported string types	Include instead of url.h
ATL/MFC	CSimpleStringT, CStringT, CFixedStringT	url_for_atl.h
Qt	QString, QStringView, QUtf8StringView	url_for_qt.h

Qt example:

#include "upa/url_for_qt.h"
#include <QString>
#include <iostream>

int main() {
    QString str{"http://example.com/"};
    upa::url url{str};
    std::cout << url.href() << '\n';
    return 0;
}

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 99.67%. Comparing base (0f3e22e) to head (9d200ba).
Report is 6 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #74      +/-   ##
==========================================
- Coverage   99.86%   99.67%   -0.20%     
==========================================
  Files          14       14              
  Lines        2306     2427     +121     
  Branches      383      382       -1     
==========================================
+ Hits         2303     2419     +116     
- Misses          3        8       +5     

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