[deviantart] rename 'external' to 'stash' (#302)

restrict extracted URLs to ones from https://sta.sh/...

docs/configuration.rst

@@ -395,18 +395,6 @@ Description Try to follow external URLs of embedded players.
 =========== =====
 
 
-extractor.deviantart.external
------------------------------
-=========== =====
-Type        ``bool``
-Default     ``false``
-Description Try to follow external URLs in description fields.
-
-            Note: deviantart.metadata_ needs to be enabled to make descriptions
-            available.
-=========== =====
-
-
 extractor.deviantart.flat
 -------------------------
 =========== =====
@@ -499,6 +487,17 @@ Description The ``refresh_token`` value you get from linking your
 =========== =====
 
 
+extractor.deviantart.stash
+--------------------------
+=========== =====
+Type        ``bool``
+Default     ``false``
+Description Extract Sta.sh resources from description texts.
+
+            Note: Enabling this option also enables deviantart.metadata_.
+=========== =====
+
+
 extractor.deviantart.wait-min
 -----------------------------
 =========== =====

docs/gallery-dl.conf

@@ -22,13 +22,13 @@
         "deviantart":
         {
             "refresh-token": null,
-            "external": false,
             "flat": true,
             "folders": false,
             "journals": "html",
             "mature": true,
             "metadata": false,
             "original": true,
+            "stash": false,
             "wait-min": 0
         },
         "exhentai":