Add centralized logger.

[jverswijver]

Adds a package level logger for the datajoint package.

Should accomplish the following:

• bring all the loggers under the same logger, in the current DJ we make loggers per module.
• convert all warnings to logs with level WARNING
• update any tests
• convert any applicable print statements to logs
  - [ ] Evaluate log DB table to see if logging needs to be added

Additional functionality requested by data science team:

- [ ] log warnings when user calls populate on empty key_source
- [ ] debug level logging for any insert/delete

• example for adding handler to the logger so they can send log output to sources other than stdout

Example for capturing the log output but maintaining dj logging

See the converted test test_limit_warning in the PR.
Basically you add a handler to the logger that sends all logs to a StringIO object and then retrieve the string from the object, then you remove the handler.

[ttngu207]

Suggesting the logging related to transaction to be set at DEBUG level

datajoint-python/datajoint/connection.py

Line 383 in 0ff34f2

logger.info("Transaction started")

datajoint-python/datajoint/connection.py

Line 391 in 0ff34f2

logger.info("Transaction cancelled. Rolling back ...")

datajoint-python/datajoint/connection.py

Line 400 in 0ff34f2

logger.info("Transaction committed and closed.")

[jverswijver]

Yes, this makes sense I will do that. @ttngu207

[guzman-raphael]

@jverswijver Great work! 💪

Mostly ready just offering further improvements.

[guzman-raphael]

@jverswijver Nice work! 🤝

[dimitri-yatsenko]

I think table_name does not include the schema name whereas full_table_name does.

Suggested change

	f"Error making {key} -> {self.target.table_name} - {error_message}"
	f"Error making {key} -> {self.target.full_table_name} - {error_message}"