Prefab-cloud-python

- adds duration support [82]

- Make additional classes visible [80]

- Split structlogger-supporting LogProcessor out, make logger_name derivation overridable [72]
- Revise logging in telemetry thread to print backtrace [71]
- Restore logging.Filter superclass on LoggerFilter [74]
- fix row-index handling when there's only a no-env-id (default) row [75]
- fix for integration test comparing outgoing telemetry data [78]

- Adds log level name to number conversion for structlog [69]

- Adds full telemetry support - will (configurably) send data back to Prefab about evaluations, logging counts, and context usage
- Reliability changes, increased test coverage
- Remove automatic `structlog` configuration. Adds helper methods to use Prefab in customer-configured structlog [40]
- Filter extracted for standard `logging` usage [32]
- Added types on client [28]
- Changed default collect_sync_interval from None to 30 seconds [54]
- Added package methods to configure, manage and reset a singleton instance of the client [53]
- logging overhaul - remove logging via client in favor of a logging filter [55], [60]
- Removed GRPC [56]
- Fix issue where client crashed in absence of HOME env var [61]
- Added global_context option [63]
- Removed namespace, other disused options [64]
- added on_ready_callback [65]

- Add support for reading config from a local JSON datafile [42]
- Add support for setting and using default contexts [43]
- Add support for encrypted config values [44]