KtLightElements: make light annotations lazier

Allow to get annotation list and to invoke `findAnnotation` without building delegate
Introduce KtLightNullabilityAnnotation which holds nullability information and is built
    before delegate is built

compiler/testData/asJava/lightClasses/SpecialAnnotationsOnAnnotationClass.kt

@@ -0,0 +1,7 @@
+// Anno
+
+@Retention(AnnotationRetention.SOURCE)
+@Target(AnnotationTarget.TYPE_PARAMETER)
+@MustBeDocumented
+@Repeatable
+annotation class Anno(val i: Int)