Cloudreactor-procwrapper

* Support sampling to avoid calling API server every time a Task executes

* Do not retry 500 response status, handle Retry-After header for retryable
statuses (now including 429 Too Many Requests)
* Fix dependencies to separate extras, not include Jinja2 version constraint

* Fix reference of ProcWrapper instance variables before definition in
constructor
* Fix --overwrite-env-during-resolution parameter to be dashed instead of
underscored, fix some usage docs
* Try to get assumed role ARN when running in CodeBuild.
* Do not refresh CodeBuild metadata as it comes from environment variables that
never change

* Refresh runtime metadata periodically

* Support sidecar container mode in AWS ECS
* Move CodeBuild source version to execution method capability (Task instead of
Task Execution)
* Stop building standalone executable with nuitka because [it doesn't respond to
signals properly](https://github.com/Nuitka/Nuitka/issues/2156)

* Read Task name even in offline mode
* Move CodeBuild initiator to execution method capability (Task instead of Task Execution)
* Send build and deploy Task Execution UUIDs