Resource Storage

Base classes to implement resource storage for cached_resource package.

Components

1. ResourceStorage: base class to implement resource storage.
2. CacheEntry: base class that holds cached value and store timestamp.
3. ResourceStorageProvider: interface for resource storage factory.
4. StorageDecoder: interface for persistent storage decoding.
5. StorageExecutor: interface for task executor that can be provided externally and its simple implementation syncStorageExecutor.
6. TimestampProvider: helper class to use in tests for mocking of timestamp.
7. Logger: base logger interface.
8. JsonStorageAdapter: helper class for toJson/fromJson conversion using provided executor.