common/utils: Add function to get origin visit types dynamically
Instead of hardcoding the list of visit types that can be used in
search queries, retrieve it dynamically using swh-search
.
Also remove visit_types
from global template context processor
and move it to seach related views only to avoid sending a
request to elasticsearch on every page load.
Related to swh-search#3441 (closed)
Migrated from D6219 (view on Phabricator)