Only course creators should be permitted to create new beta Content Libraries

[ormsbee]

Only people who can create courses should be allowed to create new content libraries. Right now, any active user can do so:

edx-platform/openedx/core/djangoapps/content_libraries/permissions.py

Lines 69 to 71 in f9126bf

	# Is the user allowed to create content libraries?
	CAN_CREATE_CONTENT_LIBRARY = 'content_libraries.create_library'
	perms[CAN_CREATE_CONTENT_LIBRARY] = is_user_active

We should be looking at course_creators. Related to this, only people who have explicit permissions or who are course_creators(or global staff) should be able to view publicly accessible content libraries.

The ENABLE_CREATOR_GROUP setting is True by default:

edx-platform/cms/envs/common.py

Lines 222 to 224 in 1397673

	# If set to True, new Studio users won't be able to author courses unless
	# an Open edX admin has added them to the course creator group.
	'ENABLE_CREATOR_GROUP': True,

Acceptance criteria:

1. When ENABLE_CREATOR_GROUP is False, only global staff may create new content libraries.
2. When ENABLE_CREATOR_GROUP is True, people in the course creator group can create content libraries, along with global staff. Other users may not create libraries.

We need to get this fixed before the Sumac release is tagged.