package_manager: Move to package_manager/__init__.py

This is part of a refactor that will split the package manager
code so that it's possible to use other package managers in other
layers.

Signed-off-by: Fredrik Gustafsson <fredrigu@axis.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

diff --git a/meta/lib/oe/package_manager.py b/meta/lib/oe/package_manager/__init__.py
similarity index 100%
rename from meta/lib/oe/package_manager.py
rename to meta/lib/oe/package_manager/__init__.py