WIP Change to chain parsing allowing for customised slignature code

This branch is to test the idea of how one can add signature customisations to the chain name parsing. It is for the preview at the moment for! @markowen, @khoo @peter

I will be away the next week so I would not mind if someone picks up. Especially that the jets need to do their own way in any case. As an example there is customisation for electrons. To be removed of course.