Improve MySQL ReadRelationships paginated throughput

[vroldanbet]

Same experiment as #1275 with MySQL

It performed well in all scenarios. Test with 153295 tuples, local MySQL and SpiceDB
Overall regression is still obvious in 2/3 scenarios

zed relationship read authzed/resource reader authzed/user --consistency-full | wc -l
No pagination: 1495.851
with tuple comparison: 47135.61ms
with expanded logic: 9718.667ms

zed relationship read authzed/resource reader --consistency-full | wc -l
No pagination: 1241.65
with tuple comparison: 40956.867ms
with expanded logic: 34398.637ms

zed relationship read authzed/resource --consistency-full | wc -l
No pagination: 1279.036
with tuple comparison: 44472.297ms
with expanded logic: 1653.474ms

current state in main

EXPLAIN ANALYZE SELECT namespace, object_id, relation, userset_namespace, userset_object_id, userset_relation, caveat_name, caveat_context
FROM relation_tuple
WHERE created_transaction <= 5 AND (deleted_transaction = 9223372036854775807 OR deleted_transaction > 9223372036854775807)
AND namespace = 'authzed/resource' AND relation = 'reader' AND ((userset_namespace = 'authzed/user'))
AND (object_id, relation, userset_namespace, userset_object_id, userset_relation) > ('1', 'reader', 'authzed/user', '38dfc848-df6f-11ed-b1b6-0242ac130002', '...')
ORDER BY namespace, object_id, relation, userset_namespace, userset_object_id, userset_relation
LIMIT 1000

"EXPLAIN"
"-> Limit: 1000 row(s)  (cost=1049.65 rows=634) (actual time=158.641..161.601 rows=1000 loops=1)
    -> Filter: ((relation_tuple.object_id,relation_tuple.relation,relation_tuple.userset_namespace,relation_tuple.userset_object_id,relation_tuple.userset_relation) > ('1','reader','authzed/user','38dfc848-df6f-11ed-b1b6-0242ac130002','...'))  (cost=1049.65 rows=634) (actual time=158.640..161.557 rows=1000 loops=1)
        -> Index lookup on relation_tuple using uq_relation_tuple_namespace (namespace='authzed/resource'), with index condition: ((relation_tuple.userset_namespace = 'authzed/user') and (relation_tuple.relation = 'reader') and (relation_tuple.created_transaction <= 5) and (relation_tuple.deleted_transaction = 9223372036854775807))  (cost=1049.65 rows=76084) (actual time=0.025..149.079 rows=50000 loops=1)
"

changes in this PR

EXPLAIN ANALYZE SELECT namespace, object_id, relation, userset_namespace, userset_object_id, userset_relation, caveat_name, caveat_context
FROM relation_tuple
WHERE created_transaction <= 5 AND (deleted_transaction = 9223372036854775807 OR deleted_transaction > 9223372036854775807)
AND namespace = 'authzed/resource' AND relation = 'reader' AND ((userset_namespace = 'authzed/user'))
AND (object_id > '1' OR (object_id = '1' AND relation > 'reader') OR (object_id = '1' AND relation = 'reader' AND userset_namespace > 'authzed/user')
     OR (object_id = '1' AND relation = 'reader' AND userset_namespace = 'authzed/user' AND userset_object_id > '38dfc848-df6f-11ed-b1b6-0242ac130002')
     OR (object_id = '1' AND relation = 'reader' AND userset_namespace = 'authzed/user' AND userset_object_id = '38dfc848-df6f-11ed-b1b6-0242ac130002' AND userset_relation > '...'))
ORDER BY namespace, object_id, relation, userset_namespace, userset_object_id, userset_relation
LIMIT 1000

"EXPLAIN"
"-> Limit: 1000 row(s)  (cost=67187.29 rows=1000) (actual time=0.033..3.458 rows=1000 loops=1)
    -> Index range scan on relation_tuple using uq_relation_tuple_namespace over (namespace = 'authzed/resource' AND object_id = '1' AND relation = 'reader' AND userset_namespace = 'authzed/user' AND userset_object_id = '38dfc848-df6f-11ed-b1b6-0242ac130002' AND '...' < userset_relation) OR (namespace = 'authzed/resource' AND object_id = '1' AND relation = 'reader' AND userset_namespace = 'authzed/user' AND '38dfc848-df6f-11ed-b1b6-0242ac130002' < userset_object_id) OR (namespace = 'authzed/resource' AND '1' < object_id), with index condition: ((relation_tuple.userset_namespace = 'authzed/user') and (relation_tuple.relation = 'reader') and (relation_tuple.namespace = 'authzed/resource') and (relation_tuple.created_transaction <= 5) and (relation_tuple.deleted_transaction = 9223372036854775807) and ((relation_tuple.object_id > '1') or ((relation_tuple.object_id = '1') and (relation_tuple.userset_object_id > '38dfc848-df6f-11ed-b1b6-0242ac130002')) or ((relation_tuple.userset_object_id = '38dfc848-df6f-11ed-b1b6-0242ac130002') and (relation_tuple.object_id = '1') and (relation_tuple.userset_relation > '...'))))  (cost=67187.29 rows=76086) (actual time=0.032..3.384 rows=1000 loops=1)