Implement Storage Plugin Interface

[mfaferek93]

Summary

Make storage pluggable. Extract SQLite to dtc_storage plugin.

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Proposed solution (optional)

Interface:

class StoragePlugin {
  virtual void store_fault(Fault) = 0;
  virtual vector<Fault> query_faults(params) = 0;
  virtual void clear_fault(id) = 0;
};

Move SQLite code to ros2_medkit_storage_plugins/dtc_storage.
Use pluginlib.

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Additional context (optional)

• Backwards compatible (default: dtc_storage)
• Document plugin development