Add helper for input/output location names for LHCb::Algorithms when they are templated
Helps to deal with situations where a templated algorithm has a templated number of input and output locations, which have to be given a name, e.g. in a MultiTransformer which returns a std::tuple, where the number of elements in that tuple is templated.
Methods for either creating input / output location names with a std::array<std::string, n> of names, or just indexing à la Output1, Output2, etc.
Addresses Rec#384 (closed)