Create a Screen base class

[gbenziv]

Probably rename screenIface to screenBase.

Move controller member to base class: T controller. Move tablehelper member. Move update() operation

void showLandingScreen() const 
void EmployeeMgmtScreen::queryEmployeesList() to void queryDataListFromCore()
void EmployeeMgmtScreen::showEmployees() const to void showDataList() const;
void showOptions const;
void EmployeeMgmtScreen::removeEmployee() to void deleteSelectedData();
void invalidOptionSelected const;

std::string getUpdateField() {
    // Get the field to update
    return SCREENCOMMON().getUpdateField(mDomainFields);
}

virtual bool action {
  return true;
}

virtual getUserSelection {
 return Options::APP_EXIT;
}

virtual fillInformation {
 // empty?
}

const std::vector<std::string> mDomainFields;
enum class Options;