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/project/annotations.py

@@ -30,6 +30,37 @@ def agent(func):
     return func
 
 
+def llm(func):
+    func.is_llm = True
+    func = memoize(func)
+    return func
+
+
+def output_json(cls):
+    cls.is_output_json = True
+    return cls
+
+
+def output_pydantic(cls):
+    cls.is_output_pydantic = True
+    return cls
+
+
+def tool(func):
+    func.is_tool = True
+    return memoize(func)
+
+
+def callback(func):
+    func.is_callback = True
+    return memoize(func)
+
+
+def cache_handler(func):
+    func.is_cache_handler = True
+    return memoize(func)
+
+
 def crew(func):
     def wrapper(self, *args, **kwargs):
         instantiated_tasks = []