[V3 Core] Moved [p]cogs command to CogManager (#1076)

* Move cogs command to CogManager

* Move cogs command to CogManager

* self.bot -> ctx.bot

* Typing

* Missing import

redbot/cogs/downloader/downloader.py

@@ -185,28 +185,6 @@ class Downloader:
         elif target.is_file():
             os.remove(str(target))
 
-    @commands.command()
-    @checks.is_owner()
-    async def cogs(self, ctx):
-        """
-        Lists all loaded and available cogs.
-        """
-        loaded = set(self.bot.extensions.keys())
-
-        all = set(await self.bot.cog_mgr.available_modules())
-
-        unloaded = all - loaded
-
-        msg = ("+ Loaded\n"
-               "{}\n\n"
-               "- Unloaded\n"
-               "{}"
-               "".format(", ".join(sorted(loaded)),
-                         ", ".join(sorted(unloaded)))
-               )
-        for page in pagify(msg, [" "], shorten_by=18):
-            await ctx.send(box(page.lstrip(" "), lang="diff"))
-
 
     @commands.group()
     @checks.is_owner()