AnalysisTop: Ability to force-revert to MC weights vector indices instead of using metadata

Since a while, we have the ability in AnalysisTop to specify nominal weight names instead of indices, and use PMGTool and metadata to determine the index of this nominal weight. For fallback scenarios, where metadata is broken, it is possible to use index in the MC weights vector instead.

We have identified corner cases, where usage of weight names is extremely impractical (long, multiline weight names with \n and # characters ?!), therefore we introduce a boolean option ForceNominalWeightFallbackIndex in config, to force usage of weight index, instead of using the metadata and the weight names, even if metadata is not broken.

Resolves ANALYSISTO-961