Improvement of Phylo user experience

1. There is a JSON in the phylo file that give the parameters that have been use to generate the phylo. It is important to give access to these parameters to the user so that they could adjust their exploration.
2. Another important information to provide while GarganText compute the phylo is the number of groups the phylo is reconstructing from. This gives an insight about how long it will take and in which direction the parameters should be adjusted.
3. Last, it would be nice to receive a mail when the phyloscript is over.

There parameters could be displayed in the legend