Add global error handler

[seratch]

Description

As with other Bolt frameworks, the error handler should be customizable.

bolt-python/slack_bolt/app/app.py

Lines 321 to 324 in 3eea0c4

	# TODO: error handler
	self._framework_logger.exception(
	f"Failed to run listener function (error: {e})"
	)

bolt-python/slack_bolt/app/async_app.py

Lines 352 to 355 in 3eea0c4

	# TODO: error handler
	self._framework_logger.exception(
	f"Failed to run listener function (error: {e})"
	)

Category (place an x in each of the [ ])

• slack_bolt.App and/or its core components
• slack_bolt.async_app.AsyncApp and/or its core components
• Adapters in slack_bolt.adapter

Requirements (place an x in each of the [ ])

• [x I've read and understood the Contributing guidelines and have done my best effort to follow them.
• I've read and agree to the Code of Conduct.
• I've searched for any related issues and avoided creating a duplicate issue here.