Locator: Move filter action creation out of input field widget

src/plugins/coreplugin/locator/ilocatorfilter.cpp

src/plugins/coreplugin/locator/ilocatorfilter.h

src/plugins/coreplugin/locator/locator.cpp

src/plugins/coreplugin/locator/locator.h

src/plugins/coreplugin/locator/locatorfiltersfilter.cpp

src/plugins/coreplugin/locator/locatorfiltersfilter.h

src/plugins/coreplugin/locator/locatormanager.cpp

src/plugins/coreplugin/locator/locatormanager.h

src/plugins/coreplugin/locator/locatorsettingspage.cpp

src/plugins/coreplugin/locator/locatorwidget.cpp

src/plugins/coreplugin/locator/locatorwidget.h