FEAT: Add Initializers module

[iraedeus]

• Add abstract class Initializer
• Add implementation of the abstract class:
  • ClusterizeInitializer
  • Some strategies for initializing parameter of mixture
• Update design docs

Reqs:

• Strategy: Q-function (@singledispatch)
• Accurate and fast init (choose clusters by score)
• Choosing soft or hard matrix
  • Check if there is exists fuzzy clusterizers in sklearn and if there is support them