rip out fetch_initial_posts

Every time someone tries to use it, it goes mad and tries to scrape the
entire fediverse for no visible reason, it's better to just remove it
than continue shipping it in it's current state.

idea acked by lain and feld on irc

Closes #1595 #1422

config/config.exs

@@ -504,10 +504,6 @@ config :pleroma, :workers,
     federator_outgoing: 5
   ]
 
-config :pleroma, :fetch_initial_posts,
-  enabled: false,
-  pages: 5
-
 config :auto_linker,
   opts: [
     extra: true,

config/description.exs

@@ -2007,25 +2007,6 @@ config :pleroma, :config_description, [
       }
     ]
   },
-  %{
-    group: :pleroma,
-    key: :fetch_initial_posts,
-    type: :group,
-    description: "Fetching initial posts settings",
-    children: [
-      %{
-        key: :enabled,
-        type: :boolean,
-        description: "Fetch posts when a new user is federated with"
-      },
-      %{
-        key: :pages,
-        type: :integer,
-        description: "The amount of pages to fetch",
-        suggestions: [5]
-      }
-    ]
-  },
   %{
     group: :auto_linker,
     key: :opts,