Implements the connection from the teams feature to the content groups feature. This implementation uses the dynamic partition generator extension point to associate content groups with the users that belong to a Team.
This implementation was heavily inspired by the enrollment tracks dynamic partitions.
This re-applies commit 36cc415 with handling an invalid context_key in the
`PartitionService`. It can happen when rendering a `LibraryContentBlock` in
Studio because this service is initialized by the modulestore when validating
an XBlock to gather its error messages in the `studio_xblock_wrapper`.
- Moving xmodule folder to root as we're dissolving sub-projects of common folder in edx-platform
- More info: https://openedx.atlassian.net/browse/BOM-2579
- -e common/lib/xmodule has been removed from the requirements as xmodule has itself become the part of edx-platform and not being installed through requirements
- The test files common/lib/xmodule/test_files/ have been removed as they are not being used anymore
