Find usages test: Move test data out of code
Move checkSuperMethods and format methods to RefactoringUtil
Extract search action name
Introduce parent class for "find usage" handlers
Allow user to find usages of overriden methods
Implement "Find usages with options" for kotlin functions
Add Kotlin delegate for Java safe delete
Add support of extension search
Simplify "Find Usages" test data, Move configuration options to test files