Stephan212 chart dynamic legend position (#2)

* Writer/Part/Chart.php Add dynamic Legend positions

The position of the legend of charts was always fixed to the right. Adding in the option to set it dynamically via a new option under styles/chart

* Update Syle/Chart.php

Add in the public functions to getStyle() to get and set the legend position

src/PhpWord/Style/Chart.php

@@ -308,6 +308,7 @@ class Chart extends AbstractStyle
      * "b" - bottom of chart
      * "t" - top of chart
      * "l" - left of chart
+     * "tr" - top right of chart
      *
      * default: right
      *