Add vector transformation in the different `GoldDoer`

**Context & Problem** Depending on the use case and embeddings, we might want to transform the features before some actions. For instance, it can be a vector normalization (having channel vectors with norm of 1), or compute residual from prototypes, ... etc There are multiple locations in the code where the transformation can be done: - `GoldDescriptor`: before storing the embeddings in the local table - `GoldVectorizer`: before storing the vectors in the local table - `GoldSelector`: before making the selection among the vectors - `GoldClusterizer`: before clustering the vectors **Proposed Solution** Like for the feature reduction, we create a base class called GoldTransformationTool. Then in all GoldDoers listed above we add it as an attribute. Then inside the computation functions, we transform the embeddings before the proper action. As a first usable tool, we can add the normalization tool.