R1:16508740048e

Modernize Drydock CLI management of task execution

Summary:
Ref T2015. Currently, Drydock has a `wait-for-lease` workflow which is invoked in the background by the `lease` workflow.

The goal of this mechanism is to allow `bin/drydock lease` to print out logs as the lease is acquired. However, this predates the `runAllTasksInProcess` flags, and they provide a simpler and more robust way (potentially with `--trace` and `PhutilConsole`) to do synchronous execution and debug logging.

Simplify this whole…