Compute deadend and orphan metabolites

[ArnaudBelcour]

To add more details on the metabolic networks used we could compute the deadend and the orphan metabolites for both individual and community.

For individual organism we could use menetools dead (for dead end). But we will have to implement menetools orphan.

For community, we will have to create a new command in miscoto, that could do both analysis (deadend + orphan).

This will create new results in the json output file.