Remove deprecated subscriptions

[angrykoala]

Description

Removes support for non-cdc subscriptions. This means the only available engine for subscriptions is Neo4jGraphQLSubscriptionsCDCEngine:

new Neo4jGraphQL({
    typeDefs,
    driver,
    features: {
        subscriptions: new Neo4jGraphQLSubscriptionsCDCEngine({
            driver,
        }),
    },
});

The default behaviour of subscriptions has also been updated to use CDC, so now passing true will use the CDC engine with the default parameters and driver:

new Neo4jGraphQL({
    typeDefs,
    driver,
    features: {
        subscriptions: true,
    },
});

---

Remove support for relationship subscriptions:

• *RelationshipCreated
• *RelatiosnhipDeleted

A follow up PR will remove the deprecated code and update cypher

[changeset-bot]

🦋 Changeset detected

Latest commit: 74dfb4b

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 4 packages

Name	Type
@neo4j/graphql	Major
neo-place	Patch
apollo-subscriptions-server	Patch
yoga-subscriptions-server	Patch

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Click here if you're a maintainer who wants to add another changeset to this PR

[darrellwarde]

The PR looks good, but I do think we should maybe re-discuss the API here?

[darrellwarde]

I think let's leave this like this like now for this PR, but after seeing this and the fact that literally the only thing that can be passed in is the CDC engine, I'm definitely camp "this should be turned into an object for configuration" - maybe a follow-up PR?

[angrykoala]

The one advantage of this is that it leaves the door open for capturing the events by extending this class, I know it is not the primary use case, but some users have been using the CDC subscriptions to capture these events for some external processing.