Add facet_fields parameter to all Bioentity routes

[deepakunni3]

@kshefchek This PR basically adds facet_fields parameter to all Bioentity routes.

And when facet_fields is None, the default subject_taxon_label and object_closure is used.
This is to ensure that we don't break any existing implementations that might assume that these fields are faceted. But this default behavior may be removed in a future release.

This PR is related to monarch-initiative/monarch-ui#168

[deepakunni3]

Travis failing due to api.mi.org being down

[kshefchek]

I reran the travis tests now that all of our services are stable, but same results. Odd, I had similar logs on my recent PR

[deepakunni3]

@kshefchek It looks like a lot of the behave tests are failing, mostly due to change in the data.
Routes that yielded results before now return empty.

Ex: /api/bioentity/publication/PMID:20220848/genotypes should return an association with object being MONARCH:FBgeno426941, but now there are no associations.

Is this expected?

[kshefchek]

This is expected, we removed fly genotypes in this release

[deepakunni3]

@kshefchek Thanks for merging the PR.

I'll fix the behave tests in a separate PR. I made some assumptions regarding the data which is likely to change from one release to another.