Add feautures for load new style string

[Jomart02]

Need to add support for adding style lines to the end of the installed one

Example

   "stringStyle": " QWidget {backgroung-color : red;} QLabel {color: {colorText}; }

First style

QDoubleSpinBox {color: {colorText}};

Result style

QDoubleSpinBox {color: {colorText}};
QWidget {backgroung-color : red;} QLabel {color: {colorText};

After that swap all keys style

This key is checked at the very beginning of reading and is written to the end of the installed style file
This key must be unique and not replaceable