Ref T10895.
Currently, many arc workflows are unnecessarily slow because they call conduit.connect on startup. There's no need to do this with the modern way the API works, and we've generally moved away from explicit version testing to more granular capability testing on specific workflows.
Additionally, some workflows like arc patch are huge messes (see T11434) because they're trying to run in anonymous mode but it doesn't really work with all the upfront stuff Conduit does now. It's not possible, in the general case, for a workflow to know upfront if it needs Conduit or not.
And:
- ArcanistWorkflow has piles of Conduit logic, but should not.
- Pooling Conduit requests isn't very easy.
- There's a lot of general cruft around the workflow.
- We should drop certificate support.
This pulls out Conduit into a separate on-demand class with modern support, future pooling, less cruft, inline handling of login issues, and generally less garbage.
Also adds an --anonymous flag, mostly to make testing easier.