Validate logical replication slot name

[rauanmayemir]

Description

In the spirit of getting familiar with the code base I added a fix with validation rules for logrepl.slotName config which I myself got bitten by.

Turns out, publications are fine with special characters in the name, but not replication slots.
Oddly, this is the only place where it's documented: https://www.postgresql.org/docs/17/warm-standby.html#STREAMING-REPLICATION-SLOTS-MANIPULATION

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