Flask-opsgenie

- New config parameter: envtype. Envtype will be added as a suffix to alert alias for environment based de-duplication of alerts.
- Removed _app_ctx_stack and use g instead to support Flask 3.x

Excluding flask 3.0.0 and above due to breaking changes.

Handle RecursionError when applying to str on exception objects.

Fixed breaking traceback.format_exception function interface for python 3.10.

Feature release:
- flask-opsgenie will now allow to forward request headers to alert.
- A new config option called FORWARDED_HEADER_KEYS has been introduced which accepts a list of request headers
- The above list of headers will be forwarded to opsgenie whenever an alert is generated.
- This should potentially help in debugging while pinpointing reuqests causing a given alert/exception.

Enhancements:
- Use exception class name in alias to cut down on length and keep the func_name-<exception> combination unique and less random
- This will help in deduplication on Opsgenie