Investigate direct usage of SNS' hierarchy API to build facets
We currently build facet paths for the various UMTHES concepts by individually retrieving tag definition starting from a given leaf tag in update_tag_def
and then recursively enumerating all its transitive parent tags and updating their tag definitions as well.
SNS actually has a dedicated API to traverse the broader/narrower relation, i.e. the hierarchy API, and we should investigate whether we can reduce the amount of HTTP call required to fetch the relevant information.