Added support for Redis 8.4 DELEX command.

[Dgramada]

This change introduces the DELEX string command feature as part of the features provided by the spring-data-redis project.

This feature is available starting from Redis OSS version 8.4 and later

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[mp911de]

Only two minor things to address. We need to discuss method naming for the API. CAS-wise, compareAndDelete(…) would be a great fit, but we have to accomodate the ifNotEquals factor.

[mp911de]

We prefer @EnabledOnCommand("DELEX") gurards

[mp911de]

@NonNull Boolean isn't right here as the return value can be null when used in transactions. Just Boolean is fine.

[Dgramada]

I should mention that CAS/CAD operations in Redis also support two more options - IF_DIGEST_EQUAL and IF_DIGEST_NOT_EQUAL, which could be added at some point as well.

Maybe we should take this into consideration, while naming the current template CAS/CAD methods.

We could then name the methods something like:

• compareAndDelete (instead of deleteIfEqual)
• compareAndDeleteIfDifferent (instead of deleteIfNotEqual)
• compareDigestAndDelete (potential name if digest logic is added at some point in the future)
• compareDigestAndDeleteIfDifferent (potential name if digest logic is added at some point in the future)

[mp911de]

We want to avoid uncontrolled growth in method (name) overload variants. Our current thinking is at compareAndDelete(K key, V oldValue, V newValue) and compareAndDelete(K key, CasOperator<V> oldValue, V newValue) where CasOperator (or a better name) can be CasOperator.ifEqual(…), CasOperator.ifNotEqual(…) and so on.