PhpUnit XML reporter

[Naktibalda]

Like Junit, but generates testsuite for each test file.

Fixes Codeception/Codeception#5004
Replaces #52

Example of report :

<?xml version="1.0" encoding="UTF-8"?>
<testsuites>
  <testsuite name="dummy" tests="6" assertions="3" errors="0" failures="0" skipped="0" time="0.328235">
    <testsuite file="/c/Projects/phpunit-wrapper/vendor/codeception/codeception/tests/data/claypit/tests/dummy/FileExistsCept.php" tests="1" assertions="1" errors="0" failures="0" skipped="0" time="0.119059">
      <testcase name="FileExists" file="/c/Projects/phpunit-wrapper/vendor/codeception/codeception/tests/data/claypit/tests/dummy/FileExistsCept.php" assertions="1" time="0.119059"/>
    </testsuite>
    <testsuite file="/c/Projects/phpunit-wrapper/vendor/codeception/codeception/tests/data/claypit/tests/dummy/AnotherCest.php" tests="2" assertions="0" errors="0" failures="0" skipped="0" time="0.078635">
      <testcase file="/c/Projects/phpunit-wrapper/vendor/codeception/codeception/tests/data/claypit/tests/dummy/AnotherCest.php" name="optimistic" class="AnotherCest" assertions="0" time="0.058278"/>
      <testcase file="/c/Projects/phpunit-wrapper/vendor/codeception/codeception/tests/data/claypit/tests/dummy/AnotherCest.php" name="pessimistic" class="AnotherCest" assertions="0" time="0.020357"/>
    </testsuite>
    <testsuite file="/c/Projects/phpunit-wrapper/vendor/codeception/codeception/tests/data/claypit/tests/dummy/GroupEventsCest.php" tests="1" assertions="0" errors="0" failures="0" skipped="0" time="0.000562">
      <testcase file="/c/Projects/phpunit-wrapper/vendor/codeception/codeception/tests/data/claypit/tests/dummy/GroupEventsCest.php" name="countGroupEvents" class="GroupEventsCest" assertions="0" time="0.000562"/>
    </testsuite>
    <testsuite file="/c/Projects/phpunit-wrapper/vendor/codeception/codeception/tests/data/claypit/tests/dummy/AnotherTest.php" tests="2" assertions="2" errors="0" failures="0" skipped="0" time="0.129979">
      <testcase name="testFirst" class="AnotherTest" classname="AnotherTest" file="/c/Projects/phpunit-wrapper/vendor/codeception/codeception/tests/data/claypit/tests/dummy/AnotherTest.php" line="4" assertions="1" time="0.126584"/>
      <testcase name="testSecond" class="AnotherTest" classname="AnotherTest" file="/c/Projects/phpunit-wrapper/vendor/codeception/codeception/tests/data/claypit/tests/dummy/AnotherTest.php" line="8" assertions="1" time="0.003395"/>
    </testsuite>
  </testsuite>
</testsuites>

New command line parameter --phpunit-xml will be added to Codeception.