[CHANGE] - Replace use of QValidator by own class

[rainman110]

Summary

The dataprocessor and core are using the QValidator class to validate string properties with mainly regexps.

Since QValidator is a QtGui class, this should be replace by an own implementation.

To be discussed:

• Do we need a Validator interface or are regexps enough?
• Do we need to mimic the QtValidator interface to keep API changes small?

Impact on the codebase

Relatively small in GTlab Core, but modules might be effected, if they are using custom validators.

Current workarounds

-

[jensschmeink]

GTlab Meeting: Prefered solution is to add an GtValidator interface Add free function to GTlab GUI to convert GtValidator to QValidator