[V3 Everything] Package bot and write setup scripts (#964)

Ya'll are gonna hate me.

* Initial modifications

* Add initial setup.py

* working setup py help

* Modify setup file to package stuff

* Move a bunch of shit and fix imports

* Fix or skip tests

* Must add init files for find_packages to work

* Move main to scripts folder and rename

* Add shebangs

* Copy over translation files

* WORKING PIP INSTALL

* add dependency information

* Hardcoded version for now, will need to figure out a better way to do this

* OKAY ITS FINALLY FUCKING WORKING

* Add this guy

* Fix stuff

* Change readme to rst

* Remove double sentry opt in

* Oopsie

* Fix this thing

* Aaaand fix test

* Aaaand fix test

* Fix core cog importing and default cog install path

* Adjust readme

* change instance name from optional to required

* Ayyy let's do more dependency injection

redbot/cogs/downloader/errors.py

@@ -0,0 +1,84 @@
+__all__ = ["DownloaderException", "GitException", "InvalidRepoName", "ExistingGitRepo",
+           "MissingGitRepo", "CloningError", "CurrentHashError", "HardResetError",
+           "UpdateError", "GitDiffError", "PipError"]
+
+
+class DownloaderException(Exception):
+    """
+    Base class for Downloader exceptions.
+    """
+    pass
+
+
+class GitException(DownloaderException):
+    """
+    Generic class for git exceptions.
+    """
+
+
+class InvalidRepoName(DownloaderException):
+    """
+    Throw when a repo name is invalid. Check
+    the message for a more detailed reason.
+    """
+    pass
+
+
+class ExistingGitRepo(DownloaderException):
+    """
+    Thrown when trying to clone into a folder where a
+    git repo already exists.
+    """
+    pass
+
+
+class MissingGitRepo(DownloaderException):
+    """
+    Thrown when a git repo is expected to exist but
+    does not.
+    """
+    pass
+
+
+class CloningError(GitException):
+    """
+    Thrown when git clone returns a non zero exit code.
+    """
+    pass
+
+
+class CurrentHashError(GitException):
+    """
+    Thrown when git returns a non zero exit code attempting
+    to determine the current commit hash.
+    """
+    pass
+
+
+class HardResetError(GitException):
+    """
+    Thrown when there is an issue trying to execute a hard reset
+    (usually prior to a repo update).
+    """
+    pass
+
+
+class UpdateError(GitException):
+    """
+    Thrown when git pull returns a non zero error code.
+    """
+    pass
+
+
+class GitDiffError(GitException):
+    """
+    Thrown when a git diff fails.
+    """
+    pass
+
+
+class PipError(DownloaderException):
+    """
+    Thrown when pip returns a non-zero return code.
+    """
+    pass