* refactor AgentExecutor, add output_response flag for switching on or off workflow output for each agent.
* introduce add_agent
* make default agent's streaming to false
* address comments
* fix test
* add is_streaming to RunnerContext and WorkflowContext
* fix add_agent return
* fix tests
* address comments
* resolve conflict
* update to address comments
* fix
* Adding more test for workflow vizualization.
* Improving README for sample.
* More cleanup.
* Removing rendering of workflow visualization and adding basic support for mermaid format.
* Adding basic mermaid tests.
* Improving sample. Switching to another branch.
* About to merge from main.
* Formatting.
* More fromatting.
* Removng uneeded call to ToUpper.
* Adding README.
* Moving samples under workflow to workflows.
* Removing uneeded README for map-reduce sample.