Remastering of documentation provider

- Remove whole file resolve
- Take already resolved element
- Get kotlin element behind the wrapper directly
- Remove outdated isKotlinDeclaration method
- More tests

idea/testData/editor/quickDoc/KotlinPackageClassUsedFromJava.java

@@ -0,0 +1,9 @@
+import testing.TestingPackage
+
+class KotlinClassUsedFromJava {
+    void test() {
+        <caret>TestingPackage.foo()
+    }
+}
+
+// INFO: [light_idea_test_case] testing...