[AA] Add stub annotationApplicableTargets extension.

Introduce an extension method to retrieve the set of applicable targets
for an annotation, given the annotation class's symbol.

This extension on `KtSymbolInfoProvider` causes a large amount of churn
in test data files, so this change starts off by introducing the
property and always making it return null. A future change will
introduce the actual behavior change, and will include the testdata
changes for the few tests that actually return useful data for this
property.

analysis/analysis-api/testData/scopes/memberScopeByFqName/java.lang.String.txt

@@ -3145,6 +3145,7 @@ KtNamedClassOrObjectSymbol:
   typeParameters: []
   visibility: Private
   getContainingModule: KtSdkModule "SDK jdk"
+  annotationApplicableTargets: null
   deprecationStatus: null
 
 KtConstructorSymbol: