Add sentinel support. Implementation possibly could use a few more checks around the restart but it's simple and small
Refactored api. Brando entry point is now Brando companion.
Brando.apply() will create a brando actor.
Brando.withSharding will create a BrandoSharded that accepts shard requests.
Brando.withSentinel will create a BrandoSentinel client that manages a BrandoSharded
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