Server Seed Override Should Not Override Server Identity

[blacklabelops]

I want to make use of the implemented seed override mechanism.

Problem: Seed override also overrides Server Identity.

Solution: In my cases server identities stay the same, please make it configurable.

See: https://github.com/Didstopia/rust-server/blob/master/start_rust.sh#L151

[stale[bot]]

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