Statsig

Target Apps for client bootstrap:
- `get_client_initialize_response` now accepts `client_sdk_key` as a parameter. This allows responses to respect [Target Apps](https://docs.statsig.com/sdk-keys/target-apps#configuring-target-apps) assigned to a client key.

Bootstrap/Datastore falls back to network:
- In the event that bootstrap or datastore fails during initialization a network request to `/download_config_specs` will be sent immediately. Previously the SDK would be left uninitialized until the next background sync

Internal Diagnostics Changes:
- Convert Diagnostics into a static class which can be used throughout the code base.
- This required the `_ConfigEvaluation()` class be moved into its own folder to prevent a circular dependency issues

**Full Changelog**: https://github.com/statsig-io/python-sdk/compare/v0.16.13...v0.17.0

- Move SpecStore network calls out of SpecStore.__init__
- Move /download_config_specs retry to background sync thread
- Fix bug where init_timeout was not gracefully timing out

**Full Changelog**: https://github.com/statsig-io/python-sdk/compare/v0.16.12...v0.16.13

* Kick off immediate async retry of download_config_specs if failed during initialize
* Fix memory leak related to async event logging
* Log diagnostics

Fixes a bug where events could be flushed on the main thread

Also removes an error that was thrown in the previous attempt, which was caught and handled but can be avoided

Fixes a bug where events could be flushed on the main thread.

* Can now read `group_name` from `get_config` and `get_experiment` evaluations
* Log diagnostics for initialize
* New top-level `flush()` API
* Local exposure deduping