extract cluster-type crate

[kevinheavey]

Problem

solana_sdk::genesis_config::ClusterType imposes a solana_sdk dep on solana_metrics. The genesis_config module is quite big when you include the other modules it pulls in, while solana_metrics only needs the ClusterType enum.

Summary of Changes

• Move ClusterType into its own crate and re-export with deprecation notice

[febo]

Looks good – indeed GenesisConfig brings lots of things that are not needed when only ClusterType is required, so it makes sense to separate them.

[febo]

@yihau Could we please accept the crate invite?

[yihau]

✅