Standard operations datatypes

[JackUrb]

Overview

As a step towards an asyncio-compatible supervisor, this change sets up some standard datatypes that the operations layer in Mephisto can use. This merges the TrackedRun and Job concepts into a singular LiveTaskRun which can track all of the operations instances relevant to a task run.

As far as the motivation goes, there is no clear way to fully remove the coupling between the different parts of the supervisor (in that different parts need to invoke functionality of each other), however I think it still makes sense to group the types of functionality into the separate abstractions. As such, each can then make calls to each other through a specified API, and we can gradually upgrade parts of that to be async.

Implementation

Creates the LiveTaskRun dataclass, which merges TrackedRun and Job, and then updates a bunch of callsites to use the new functionality.

Testing

Automated tests are passing