Refactor combobox remove redundant elementfinder #9 (#37)

* refactored state of elements * re-check waitForNotExists methods for correct work. split 1 test to 2, added verification of wait time * removed IElementWithState interface changed IElementStateProvider interface: added methods for waitings with default condition timeouts excluded ability to call state methods directly from elements, now users have to use state() method * refactored conditional wait refactored elements' states added isClickable * removed redundant ElementFinder usage from getSelectedText() and getValuesList() #9

Author: aquality-automation