Yapapi

Fixes
* Handle activity creation failures in spawn_instance (458)
* Repeat Payment API calls on timeout errors (473)
* Close async generators created by Executors on Golem shutdown (482)

Minor changes
* Align logs datetime format with yagna - add milliseconds and a TZ offset (463)

Updates and fixes to the examples
* Remove unneeded constants from the simple-service-poc example (462)
* Fix import path to Service class in the hello-service example (471)
* Replace NamedTemporaryFile usage in yacat example (488)
* Add default value to yacat keyspace (490)

Integration test updates
* Make goth runs compatible with yagna 0.7 (470)
* Use dynamic stable branch in goth nightly (480)

Changelog

Major changes
* Make `Golem` class the new entrypoint for the API, extract common parts into an the internal `_Engine` (365)
* Add `yapapi.service` - new high-level API for Services (383)

Additonal features
* Enable using asynchronous task iterators as sources of tasks (360)
* Add support for execution script output capturing (with optional blocking) (367)
* Add `WorkContext.terminate()` method (411)
* Allow parametrization of `WorkContext.start()` (409)
* New example: Simple Service POC (303)
* New examples: minimal batch and minimal service (421)

Fixes
* Update versions for some dependencies to fix `poetry` solver issues (395)
* Fix passing command errors from the engine to worker functions (394)
* Wait for instance tasks before shutting down a `Cluster` (423)
* Always cancel `process_invoices_job` when shutting down the `Golem` engine (452)
* Silence `asyncio.CancelledError` when awaiting the just-cancelled task (449)

Documentation updates
* Adjust `README.md` to changes in the API (451)
* Add missing docstrings for public classes and methods (416)
* Add a docstring for the `Golem` class (447)
* Add some comments to the `SmartQueue` (357)
* fix `DemandBuilder` example usage (382)

Other updates
* Refactor `yacat` example to use the updated API (403)
* Blender example: do not overwrite blender example debug logs (361)
* Replace `message` in events.CommandExecuted with `stdout` and `stderr` (379)
* Immediately terminate agreement after service instance finishes (420)
* Move `Golem` and `Job` from `yapapi.executor.__init__` to `yapapi.golem` (431)
* Move some modules from `yapapi/executor` to `yapapi/` (434)
* Make the default `Service.run()` await indefinitely instead of yielding `None` in a loop (448)
* Make summary logger the default event consumer (428)
* Use `devnet-beta.2` as the default subnet in examples (413)

Internal changes
* Make `find_offers()` an `Executor` method; handle offer proposals concurrently (306)
* Refactor `SmartQueue` to work correctly with asynchronous task iterators (399)
* Enable multiplexing of command batches and control signals in the services' state handler (408)

Integration testing
* Add an integration test that starts blender example in `goth` (281)
* Add an integration test for multi-activity agreement (350)
* Add nightly workflows for `goth` tests (363)
* Use `goth` package from PyPI (309)
* Bump `goth` version to 0.3.* (405)