Currently, we have many packages which rely on @azure/abort-controller 1.x which provided an AbortController, an AbortSignal and an AbortError. Since moving to Node 18.x, we no longer need to provide our own implementations for AbortSignal and AbortController.

The 1.x API has some non-standard behavior such as the following:

• AbortController.timeout which was standardized to AbortSignal.timeout
• AbortController.ctor takes an overload of parent AbortSignal instances that the standard does not.
• AbortController.none is also gone.

We need to provide a migration guide for moving from 1.x to 2.x.