Support negative optimizer hints

Support negative hints in relational-style optimizer hints.

The following hints will be supported:

NO_INDEX(keyspace <optional list of indexes>)

NO_INDEX_FTS(keyspace <optional list of indexes>)

NO_USE_HASH(<list of keyspaces>)

NO_USE_NL(<list of keyspaces>)

The NO_INDEX hint is similar in syntax to INDEX hint, except that any index listed is NOT to be considered by the planner.

The NO_INDEX_FTS hint is similar in syntax to INDEX_FTS hint, except that any (fts) index listed is NOT to be considered by the planner.

The NO_USE_HASH hint is similar to USE_HASH hint, with one difference: in USE_HASH hint, you can optionally specify a '/BUILD' or '/PROBE' option for each keyspace. This is not available in NO_USE_HASH hint. Only keyspace name is allowed. The planner will NOT consider hash join for any keyspace listed in NO_USE_HASH hint.

The NO_USE_NL hint is similar to USE_NL hint. The planner will NOT consider nested-loop join for any keyspace listed in NO_USE_NL hint.

In addition to the NO_ and NO_USE_ version of negative optimizer hints, we also allow AVOID_ variant as an alias:

AVOID_INDEX:     same as NO_INDEX

AVOID_INDEX_FTS: same as NO_INDEX_FTS

AVOID_NL:        same as NO_USE_NL

AVOID_HASH:      same as NO_USE_HASH