instagram: add fetching using bearer token (#487)

for total of SEVEN methods of getting post info, i cannot bear this anymore

also prevent repetitive oembed pulling

docs/examples/cookies.example.json

@@ -2,6 +2,9 @@
     "instagram": [
         "mid=<replace>; ig_did=<with>; csrftoken=<your>; ds_user_id=<own>; sessionid=<cookies>"
     ],
+    "instagram_bearer": [
+        "token=<token_with_no_bearer_in_front>", "token=IGT:2:<looks_like_this>"
+    ],
     "reddit": [
         "client_id=<replace_this>; client_secret=<replace_this>; refresh_token=<replace_this>"
     ],