KAFKA-19434: Startup state stores initialization

[eduwercamacaro]

This pull request suggests adding a new stage for the state store lifecycle.

Since we don't open and/or initialize temporary tasks, we can fix the issue described in this issue: KAFKA-19434 by modifying the state store refactor. It is now possible to pre-initialize state stores and make them readable, which also is required by KIP-1035 implementation.