refactor!: Remove Request.id field (#553)

### Description

- Remove `request.id` and replace all usages of `id` with `unique_key`
- Add transformation from `unique_key` to `id` and use it when calling
id-based client methods
- Requires:
  - apify/crawlee-python#1366

### Issues

- Part of: apify/crawlee-python#1358

Author: Pijukatel

docs/03_concepts/code/03_rq.py

@@ -20,13 +20,10 @@ async def main() -> None:
 
         # If you try to add an existing request again, it will not do anything
         add_request_info = await queue.add_request(
-            Request.from_url('http://different-example.com/5')
+            Request.from_url('http://example.com/5')
         )
         Actor.log.info(f'Add request info: {add_request_info}')
 
-        processed_request = await queue.get_request(add_request_info.id)
-        Actor.log.info(f'Processed request: {processed_request}')
-
         # Finally, process the queue until all requests are handled
         while not await queue.is_finished():
             # Fetch the next unhandled request in the queue

docs/04_upgrading/upgrading_to_v3.md

@@ -1,6 +1,6 @@
 ---
-id: upgrading-to-v2
-title: Upgrading to v2
+id: upgrading-to-v3
+title: Upgrading to v3
 ---
 
 This page summarizes the breaking changes between Apify Python SDK v2.x and v3.0.

src/apify/scrapy/requests.py

@@ -122,7 +122,7 @@ def to_scrapy_request(apify_request: ApifyRequest, spider: Spider) -> ScrapyRequ
 
         # Update the meta field with the meta field from the apify_request
         meta = scrapy_request.meta or {}
-        meta.update({'apify_request_id': apify_request.id, 'apify_request_unique_key': apify_request.unique_key})
+        meta.update({'apify_request_unique_key': apify_request.unique_key})
         # scrapy_request.meta is a property, so we have to set it like this
         scrapy_request._meta = meta  # noqa: SLF001
 
@@ -134,7 +134,6 @@ def to_scrapy_request(apify_request: ApifyRequest, spider: Spider) -> ScrapyRequ
             url=apify_request.url,
             method=apify_request.method,
             meta={
-                'apify_request_id': apify_request.id,
                 'apify_request_unique_key': apify_request.unique_key,
             },
         )

src/apify/storage_clients/_apify/_models.py

@@ -94,8 +94,8 @@ class CachedRequest(BaseModel):
     Only internal structure.
     """
 
-    id: str
-    """The ID of the request."""
+    unique_key: str
+    """Unique key of the request."""
 
     was_already_handled: bool
     """Whether the request was already handled."""