Implement a new capsula.run decorator

[shunichironomura]

• Rename capsule.py to _capsule.py and update imports
• Add default method to GitRepositoryContext class
• Add Reporter to all in capsula/reporter/init.py
• Update json reporter to handle exceptions and tracebacks
• Refactor normalize_copy_dst_path to its own method
• Update import path for Capsule in encapsulator.py
• Add capsule decorator for encapsulation logic
• Add decorator example for pi calculation
• Fix for Python 3.8 compatibility
• Add context_manager example in capsula module
• Refine type annotations in capsule decorator
• Add record function to capsula module
• Update calculate_pi method and import Encapsulator
• Add thread-local context stack to Encapsulator class
• Implement record method in _record.py
• Refactor Encapsulator instantiation in context_manager
• Add mkdir option to JsonDumpReporter constructor
• Refactor context_manager.py for cleaner code
• Rename _get_encapsulator_context_stack to _get_context_stack
• Update context manager in capsula.run usage
• Update context manager in capsula run method
• Rename _record.py to _root.py in capsula module
• Update import statement in capsula/init.py
• Refactor decorators and add TimeWatcher in decorator.py
• Rename submodule context to _context
• Rename submodule reporter to _reporter
• Add new context classes and reporter to init.py
• Refactor: Move watcher and reporter modules to private scope
• Add Watcher, TimeWatcher, UncaughtExceptionWatcher to init.py
• Refactor code to use fully qualified names
• Refactor Run to Encapsulator in context_manager
• Rename context_manager.py to enc_context_manager.py
• Add watcher, reporter and context decorators
• Add new decorators to capsula init.py
• Refactor GitRepositoryContext to use CapsuleParams
• Rename classes to end with 'Base' for clarity
• Add run.py with Run class and encapsulation methods
• Refactor decorators to support Run objects
• Add 'run' to decorators in capsula init file
• Update decorator and calculate_pi function call
• Add directory creation and phase updates in Run class
• Add FileContext decorator to calculate_pi function
• Update context_manager_stack.get to non-blocking
• Refactor encapsulator context stack naming and get
• Add thread-local run stack to Run class