Feat yaml config all attributes (#985)

* WIP: yaml proper mapping for agents and agent

* WIP: added output_json and output_pydantic setup

* WIP: core logic added, need cleanup

* code cleanup

* updated docs and example template to use yaml to reference agents within tasks

* cleanup type errors

* Update Start-a-New-CrewAI-Project.md

---------

Co-authored-by: João Moura <joaomdmoura@gmail.com>

src/crewai/cli/templates/config/tasks.yaml

@@ -5,6 +5,7 @@ research_task:
     the current year is 2024.
   expected_output: >
     A list with 10 bullet points of the most relevant information about {topic}
+  agent: researcher
 
 reporting_task:
   description: >
@@ -13,3 +14,4 @@ reporting_task:
   expected_output: >
     A fully fledge reports with the mains topics, each with a full section of information.
     Formatted as markdown without '```'
+  agent: reporting_analyst