Add support for External Memory (the future replacement for UserMemory) (#2510)

* fix: surfacing properly supported types by Mem0Storage

* feat: prepare Mem0Storage to accept config paramenter

We're planning to remove `memory_config` soon. This commit kindly prepare this storage to accept the config provided directly

* feat: add external memory

* fix: cleanup Mem0 warning while adding messages to the memory

* feat: support set the current crew in memory

This can be useful when a memory is initialized before the crew, but the crew might still be a very relevant attribute

* fix: allow to reset only an external_memory from crew

* test: add external memory test

* test: ensure the config takes precedence over memory_config when setting mem0

* fix: support to provide a custom storage to External Memory

* docs: add docs about external memory

* chore: add warning messages about the deprecation of UserMemory

* fix: fix typing check

---------

Co-authored-by: Lorenze Jay <63378463+lorenzejay@users.noreply.github.com>

src/crewai/memory/external/external_memory.py

@@ -0,0 +1,61 @@
+from typing import TYPE_CHECKING, Any, Dict, Optional, Self
+
+from crewai.memory.external.external_memory_item import ExternalMemoryItem
+from crewai.memory.memory import Memory
+from crewai.memory.storage.interface import Storage
+
+if TYPE_CHECKING:
+    from crewai.memory.storage.mem0_storage import Mem0Storage
+
+
+class ExternalMemory(Memory):
+    def __init__(self, storage: Optional[Storage] = None, **data: Any):
+        super().__init__(storage=storage, **data)
+
+    @staticmethod
+    def _configure_mem0(crew: Any, config: Dict[str, Any]) -> "Mem0Storage":
+        from crewai.memory.storage.mem0_storage import Mem0Storage
+
+        return Mem0Storage(type="external", crew=crew, config=config)
+
+    @staticmethod
+    def external_supported_storages() -> Dict[str, Any]:
+        return {
+            "mem0": ExternalMemory._configure_mem0,
+        }
+
+    @staticmethod
+    def create_storage(crew: Any, embedder_config: Optional[Dict[str, Any]]) -> Storage:
+        if not embedder_config:
+            raise ValueError("embedder_config is required")
+
+        if "provider" not in embedder_config:
+            raise ValueError("embedder_config must include a 'provider' key")
+
+        provider = embedder_config["provider"]
+        supported_storages = ExternalMemory.external_supported_storages()
+        if provider not in supported_storages:
+            raise ValueError(f"Provider {provider} not supported")
+
+        return supported_storages[provider](crew, embedder_config.get("config", {}))
+
+    def save(
+        self,
+        value: Any,
+        metadata: Optional[Dict[str, Any]] = None,
+        agent: Optional[str] = None,
+    ) -> None:
+        """Saves a value into the external storage."""
+        item = ExternalMemoryItem(value=value, metadata=metadata, agent=agent)
+        super().save(value=item.value, metadata=item.metadata, agent=item.agent)
+
+    def reset(self) -> None:
+        self.storage.reset()
+
+    def set_crew(self, crew: Any) -> Self:
+        super().set_crew(crew)
+
+        if not self.storage:
+            self.storage = self.create_storage(crew, self.embedder_config)
+
+        return self