ReactiveMutableMap.ReplayStrategy removal

[osipxd]

Pros:

• Replay strategies are source of bugs, and it is 3x harder to implement and test new features
• Strategies is the only thing that differs Rx and Coroutines implementation of ReactiveMutableMap. Behavior of mapmemory-coroutines is the same as REPLAY_LAST strategy
• REPLAY_LAST is the default strategy already. Strategies removal should not affect most of the users.

Cons:

• Someone uses strategies different from REPLAY_LAST
  If you are the person who uses strategies, please let me know. Provide your use-case in comments