s/redis/valkey/ single commit with fixes

[aiven-sal]

I'm pretty sure I overlooked something.
But all tests pass locally.
I don't expect the CI to work 100% yet, but we should fix it before we merge.

[mkmkme]

Thanks a lot for the pull request, Salvatore! Great job!

I've left some of the nitpicks I managed to get during the review. I believe, though, that the only types that actually have to be changed before merge are:

1. Automatic changes in words "storedist" and "redistribution"
2. Links to the old issues
3. An unchanged link to redis.io

Everything else (including multiple references to the "old valkey version" and "old valkey-py version") can be addressed later.

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[aiven-sal]

Most issues should be fixed. If I put a 👍 under your comment, please check if the solution is satisfying and resolve the conversation or comment again.
If I didn't put any 👍 under your comment, I'm saving it for later.
Thanks :)

[mkmkme]

Most of the comments have been fixed, but I still found a couple of places that should be changed before we merge this one

[mkmkme]

LGTM.

Thanks again for the great job!