Add support for `GETEX` and `GETDEL` through imperative and reactive `…ValueOperations`

Add support in `BoundValueOperations`, imperative and reactive `…ValueOperations` and on the connection level.

On the operations level we could have:

```java
V getAndExpire(K key, long timeout, TimeUnit unit);

V getAndExpire(K key, Duration timeout);

V getAndPersist(K key);

V getAndDelete(K key);
```

See https://redis.io/commands/getex and https://redis.io/commands/getdel