When the database's collation is not "C", the DB order is not the same as the
Rust order. As such, asserting that the elements are in increasing order fails.
However, since both queries get the order from the database, they should be in
the same order.
With too many users, the query had a giant filter `IN (u1, u2, u3,
...)`. In PostgreSQL, we can pass the users as an array instead, but that
doesn't work with SQLite. Instead, we repeat the filter from the
previous query to get the same users/groups, as a subquery.
The entire internals of the server now work using only NaiveDateTime,
since we know they are all UTC. At the fringes (LDAP, GraphQL, JWT
tokens) we convert back into UTC to make sure we have a clear API.
This allows us to be compatible with Postgres (which doesn't support
DateTime<UTC>, only NaiveDateTime).
This change is backwards compatible since in SQlite with
Sea-query/Sea-ORM, the UTC datetimes are stored without a timezone, as
simple strings. It's the same format as NaiveDateTime.
Fixes#87.
