Before these changes, we could create a materialized
view specifying its ID, but the option was ignored.
This commit makes Scylla respect the option. Now specifying
the ID results in the MV being created with that specific ID.
This way, Scylla's behavior is consistent with Cassandra's.
Because Cassandra doesn't mention the option in its
user documentation, we don't update it either in case
the semantics of it changes in the future -- we want
to have an open door for any modifications.
Note that Cassandra returns a server error if the provided
ID is already in use, both in the case of regular tables
and MVs. That's most likely a bug. Instead of following that
behavior, we stay consistent with the current semantics of
creating a regular table in Scylla: if the provided ID is
already used, return an InvalidRequest.
The last thing worth pointing out is Cassandra handles
`WITH ID = null` as a special case; normally, specifying
an invalid ID results in a ConfigurationException, but a null
is treated as a syntax error. As in the previous paragraph,
we stay consistent with the semantics of regular tables and
all invalid IDs, null included, lead to a ConfigurationException.
We also add a few short tests verifying that the implementation
works as intended.
552c752005