Add StringCommand for a SET with GET option

[galingerv]

It would be great to have a method in RedisStringCommands that would allow a SET command with GET option, which is available since Redis 6.2.0 according to the documentation of Redis. Furthermore, I would like to use it with NX option, like SET key value NX GET EX seconds, which is available since 7.0.0

[mp911de]

We do not expose an API for Redis commands introduced with Redis 7 yet. However, this would be a neat enhancement.