add time unit for ttl param

[razertory]

Feature Request

Is your feature request related to a problem? Please describe:

Describe the feature you'd like:
When I use RawKVClientBase methods, such as void put(ByteString key, ByteString value, long ttl). The ttl param need time unit for better use

Describe alternatives you've considered:
I'll add a PR for this feature. Such as default void put(ByteString key, ByteString value, long duration, TimeUnit timeUnit)

Teachability, Documentation, Adoption, Migration Strategy: