Update "default" to "auto" for clarity, update docs

src/auto_archiver/modules/generic_extractor/__manifest__.py

@@ -75,9 +75,9 @@ If you are having issues with the extractor, you can review the version of `yt-d
             "help": "Use to limit the number of videos to download when a channel or long page is being extracted. 'inf' means no limit.",
         },
         "bguils_po_token_method": {
-            "default": "default",
+            "default": "auto",
             "help": "Set up a Proof of origin token provider. This process has additional requirements. See [authentication](https://auto-archiver.readthedocs.io/en/latest/how_to/authentication_how_to.html) for more information.",
-            "choices": ["default", "script", "disabled"],
+            "choices": ["auto", "script", "disabled"],
         },
         "extractor_args": {
             "default": {},

src/auto_archiver/modules/generic_extractor/generic_extractor.py

@@ -88,7 +88,7 @@ class GenericExtractor(Extractor):
             logger.warning("Proof of Origin Token generation is disabled.")
             return
 
-        if self.bguils_po_token_method == "default" and not in_docker:
+        if self.bguils_po_token_method == "auto" and not in_docker:
             logger.info(
                 "Proof of Origin Token method not explicitly set. "
                 "If you're running an external HTTP server separately, you can safely ignore this message. "