Toml configuration file

[LouisCarpentier42]

Currently, a configuration for a workflow can be defined as a json, which can be read using the workflow.workflow_from_config method. However, this method only allows to read files in json format currently. It might be useful to also allow for toml files to be read, which offer a more readable syntax than json files. Additionally, this allows the user tochose which format for configuration file he prefers.