Feature: cache validation rules

[k0ka]

resolves #2018

• [x] Added or updated tests
• [x] Documented user facing changes
• [x] Updated CHANGELOG.md

Changes

Added possibility to cache query validation successful result. So the 2nd time the query would appear, most validator won't run against it.

Notes:

• added hash to \Nuwave\Lighthouse\Schema\AST\DocumentAST
• created interface ProvidesCacheableValidationRules which extends ProvidesValidationRules for backward compatibility. In the next release we might remove ProvidesValidationRules.
• some execution paths doesn't provide query hash, so they won't use this feature
  • Defer::executeDeferred
  • SubscriptionBroadcaster::broadcast
  • AsyncMutation::handle
• validation cache is disabled by default for now.
• it only caches successful results as Errors might fail to serialize.
• passing hashes with schema and query is quite ugly https://github.com/nuwave/lighthouse/blob/0d8ea1665f5ded77ad7ba6dde2aec8c703e6b368/src/GraphQL.php#L393-L397 but these objects are created by webonyx/graphql-php, so there is no easy way to extend them and store hashes inside objects.

I also added different benchmarks. HugeRequestBench creates requests with a lot of simple fragments: 1, 10 and 100 for benchmark1, benchmark10 and benchmark100 respectively. Enabling validation cache improves execution time:

• benchmark1 from 4.222ms to 2.886ms
• benchmark10 from 14.984ms to 4.429ms
• benchmark100 from 189.641ms to 19.783ms

[k0ka]

Hello @spawnia,

do you have time to check this PR? It significantly improves speed and is disabled by default. So it won't break backward compatibility and we can gradually test it on real loads.

[spawnia]

Released with https://github.com/nuwave/lighthouse/releases/tag/v6.45.0.