[BD-14] Migrate all environments to use database-backed organizations (#25153)

* Install `organizations` app into LMS and Studio non-optionally.
* Add toggle `ORGANIZATIONS_AUTOCREATE` to Studio.
* Remove the `FEATURES["ORGANIZATIONS_APP"]` toggle.
* Use the new `organizations.api.ensure_organization` function to
  either validate or get-or-create organizations, depending
  on the value of `ORGANIZATIONS_AUTOCREATE`,
  when creating course runs and V2 content libraries.
  We'll soon use it for V1 content libraries as well.
* Remove the `util.organizations_helpers` wrapper layer
  that had to exist because `organizations` was an optional app.
* Add `.get_library_keys()` method to the Split modulestore.
* Add Studio management command for backfilling organizations tables
  (`backfill_orgs_and_org_courses`).

For full details, see
https://github.com/edx/edx-organizations/blob/master/docs/decisions/0001-phase-in-db-backed-organizations-to-all.rst

TNL-7646

common/lib/xmodule/xmodule/modulestore/mixed.py

@@ -327,6 +327,23 @@ class MixedModuleStore(ModuleStoreDraftAndPublished, ModuleStoreWriteBase):
                     courses[course_id] = course
         return list(courses.values())
 
+    def get_library_keys(self):
+        """
+        Returns a list of all unique content library keys in the mixed
+        modulestore.
+
+        Returns: list[LibraryLocator]
+        """
+        all_library_keys = set()
+        for store in self.modulestores:
+            if not hasattr(store, 'get_library_keys'):
+                continue
+            all_library_keys |= set(
+                self._clean_locator_for_mapping(library_key)
+                for library_key in store.get_library_keys()
+            )
+        return list(all_library_keys)
+
     @strip_key
     def get_library_summaries(self, **kwargs):
         """

common/lib/xmodule/xmodule/modulestore/split_mongo/split.py

@@ -1073,6 +1073,19 @@ class SplitMongoModuleStore(SplitBulkWriteMixin, ModuleStoreWriteBase):
             )
         return courses_summaries
 
+    def get_library_keys(self):
+        """
+        Returns a list of all unique content library keys in the Split
+        modulestore.
+
+        Returns: list[LibraryLocator]
+        """
+        return list({
+            self._create_library_locator(library_index, branch=None)
+            for library_index
+            in self.find_matching_course_indexes(branch="library")
+        })
+
     @autoretry_read()
     def get_library_summaries(self, **kwargs):
         """

common/lib/xmodule/xmodule/modulestore/tests/test_libraries.py

@@ -145,6 +145,13 @@ class TestLibraries(MixedSplitTestCase):
         result = self.store.get_library(LibraryLocator("non", "existent"))
         self.assertEqual(result, None)
 
+    def test_get_library_keys(self):
+        """ Test get_library_keys() """
+        libraries = [LibraryFactory.create(modulestore=self.store) for _ in range(3)]
+        lib_keys_expected = {lib.location.library_key for lib in libraries}
+        lib_keys_actual = set(self.store.get_library_keys())
+        assert lib_keys_expected == lib_keys_actual
+
     def test_get_libraries(self):
         """ Test get_libraries() """
         libraries = [LibraryFactory.create(modulestore=self.store) for _ in range(3)]