Python: Re-introduce old dataflow configs .qll files

and move all the old deprecated aliases to that file. We now have a
situation where all queries should work as they did before, and we just
have these new Query.qll files that contain the implementation.

(deprecation comes later)

python/ql/lib/semmle/python/security/dataflow/CodeInjectionQuery.qll

@@ -28,10 +28,3 @@ import semmle.python.dataflow.new.TaintTracking
       guard instanceof SanitizerGuard
     }
   }
-
-/**
- * DEPRECATED: Don't extend this class for customization, since this will lead to bad
- * performance, instead use the new `CodeInjectionCustomizations.qll` file, and extend
- * its' classes.
- */
-deprecated class CodeInjectionConfiguration = CodeInjection::Configuration;