feat: Implement log storage polymorphism

[jopemachine]

Prerequisites of #124.
Resolves #85, #133.

• Implement MemStorage for testing
• Implement log storage polymorphism
  • Now we can build it so that only the necessary crates for each storage are included in the binaries.
• Separate raftify_cli into a standalone crate
  • The raftify_cli crate is separated into its own crate because it needs to include all storage dependencies.
• Change the WAL bootstrap method.
  • Now WAL log is used automatically if available, and only receive from the config whether to bootstrap from a snapshot or not.

Note: While it is possible to define a PyStorage type in Python to allow for custom storage, it would not perform well, and since no useful examples of its application have been found, we will not proceed with this approach. Instead, let's move the storage object creation logic into the Raft.bootstrap() method, and configure the raftify-py package to build a separate whl file for each storage type during the build process.

[jopemachine]

Remaining tasks: Python bindings and documentation update.