Decouple ReAct Loop From ToolkitTask

[collindutter]

• I have read and agree to the contributing guidelines.

Is your feature request related to a problem? Please describe.
TookitTask is tightly coupled to the ReAct prompting loop.

Describe the solution you'd like
A way to swap out different types of prompting loops like Tree of Thoughts.

Describe alternatives you've considered
Implementing these various solutions with a state machine.

[collindutter]

Related #1471