All fieldnames which are part of a query should
have an index for performance reasons. This is
even enforced on some qdrant cluster like those
on qdrant.io, and queries using a unindexed column
fail with an error.
The prefix string for qdrant collection is now
configurable, which means the same qdrant cluster
can be used to host more open webui instances and
to be able to separate the collections between the
different owui instances.