Support policy variable replacement (#7085)

This PR supports iam and bucket policies to have
policy variable replacements in resource and
condition key values.

For example
- ${aws:username}
- ${aws:userid}

pkg/policy/condition/stringlikefunc.go

@@ -51,8 +51,10 @@ func (f stringLikeFunc) evaluate(values map[string][]string) bool {
 		requestValue = values[f.k.Name()]
 	}
 
+	fvalues := f.values.ApplyFunc(substFuncFromValues(values))
+
 	for _, v := range requestValue {
-		if !f.values.FuncMatch(wildcard.Match, v).IsEmpty() {
+		if !fvalues.FuncMatch(wildcard.Match, v).IsEmpty() {
 			return true
 		}
 	}