Having multiscope in the filterTerm definition

[costero-e]

Solution proposed by @redmitry to attach information about the scope it applies for filtering terms.

{
    "id": "LOINC:3141-9",
    "label": "Weight",
    "type": "alphanumeric",
    "scope": ["individual", "biosamples", ...]
}

In this case, as filtering terms can be used for different scopes, adding multiscope information would solve the problem (if there is one) about where can a filtering term apply.
In my opinion, this is good for some models but for other models this can be a headache, so I would say this a good solution (and I would adopt it) to make life easier in some models but should be "optional" and not "required".

[costero-e]

Closing issue. See #94