Pipelines: Allow toggling a rule being enabled/disabled

## What?

Allow toggling a pipeline rule to be enabled/disabled.

## Why?

Currently, the workflow to disable a pipeline rule requires completely removing it from the pipeline phase. While this is funcitonal, there are times when it is very helpful to temporarily disable a pipeline rule. Leaving the rule in place and disabling it can help reduce errors when adding the rule back. This workflow can also better support automations that may need or want to temporarily enable a pipeline rule (a crude example is temporarily dropping messages from a "misbehaving" device).