filter list_biosources by extra metadata

[felipealbrecht]

implement: list_biosources({value:key, value2: key2})

useful for getting biosources from ontology id:

list_biosources({"term_id":"EFO:0001187"})

This task is required by MPIIComputationalEpigenetics/DeepBlue-Populator#10

Do not forget to:

• [ ] Change normal API
• [ ] Change API 2.0
• [ ] Change Middleware
• [ ] Change front-end

[felipealbrecht]

• [X] Change normal API
• [X] Change API 2.0
• [X] Change Middleware
• [X] Change front-end