[V3 Downloader] Make hidden hidden and add disabled (#1828)

* Make hidden hidden and add disabled

* Add documentation

docs/framework_downloader.rst

@@ -29,7 +29,9 @@ Keys specific to the cog info.json (case sensitive)
 
 - ``bot_version`` (list of integer) - Min version number of Red in the format ``(MAJOR, MINOR, PATCH)``
 
-- ``hidden`` (bool) - Determines if a cog is available for install.
+- ``hidden`` (bool) - Determines if a cog is visible in the cog list for a repo.
+
+- ``disabled`` (bool) - Determines if a cog is available for install.
 
 - ``required_cogs`` (map of cogname to repo URL) - A map of required cogs that this cog depends on.
   Downloader will not deal with this functionality but it may be useful for other cogs.

redbot/cogs/downloader/downloader.py

@@ -394,7 +394,11 @@ class Downloader:
             )
         cogs = repo_name.available_cogs
         cogs = _("Available Cogs:\n") + "\n".join(
-            ["+ {}: {}".format(c.name, c.short or "") for c in cogs if c not in installed]
+            [
+                "+ {}: {}".format(c.name, c.short or "")
+                for c in cogs
+                if not (c.hidden or c in installed)
+            ]
         )
         cogs = cogs + "\n\n" + installed_str
         for page in pagify(cogs, ["\n"], shorten_by=16):

redbot/cogs/downloader/installable.py

@@ -75,6 +75,7 @@ class Installable(RepoJSONMixin):
         self.bot_version = (3, 0, 0)
         self.min_python_version = (3, 5, 1)
         self.hidden = False
+        self.disabled = False
         self.required_cogs = {}  # Cog name -> repo URL
         self.requirements = ()
         self.tags = ()
@@ -173,6 +174,12 @@ class Installable(RepoJSONMixin):
             hidden = False
         self.hidden = hidden
 
+        try:
+            disabled = bool(info.get("disabled", False))
+        except ValueError:
+            disabled = False
+        self.disabled = disabled
+
         self.required_cogs = info.get("required_cogs", {})
 
         self.requirements = info.get("requirements", ())

redbot/cogs/downloader/repo_manager.py

@@ -470,7 +470,7 @@ class Repo(RepoJSONMixin):
         """
         # noinspection PyTypeChecker
         return tuple(
-            [m for m in self.available_modules if m.type == InstallableType.COG and not m.hidden]
+            [m for m in self.available_modules if m.type == InstallableType.COG and not m.disabled]
         )
 
     @property