Add class for XML Attributes meant to hold an identifier in AndroidManifest

Some Android component attributes hold an identifier (e.g.
`android:name` and `android:targetActivity` for `<activity-alias>`).

java/ql/lib/semmle/code/xml/AndroidManifest.qll

@@ -212,6 +212,13 @@ class AndroidPermissionXmlAttribute extends XmlAttribute {
   predicate isWrite() { this.getName() = "writePermission" }
 }
 
+/**
+ * The attribute `android:name` or `android:targetActivity`.
+ */
+class AndroidIdentifierXmlAttribute extends AndroidXmlAttribute {
+  AndroidIdentifierXmlAttribute() { this.getName() = ["name", "targetActivity"] }
+}
+
 /**
  * The `<path-permission`> element of a `<provider>` in an Android manifest file.
  */