* feat: add xblock endpoint for updating an xblock
fix: remove debugger
feat: make function call more generic
refactor: just use request.json for request data as before
refactor: extract method
fix: revert wrong method change
fix: refactor correct method
feat: use handle_xblock method so that we can do more than update xblocks
fix: usage_key_string defaults to None
add all CRUD operations
fix usage key parameter
refactor: create /views folder
refactor: move xblock view functions to xblock_services
fix: tests
fix: tests
refactor: move xblock API endpoint to contentstore
* docs: add explanatory comment to new xblock_service
* feat: add feature flag for enabling content editing api
* feat: raise 404 if studio content api is disabled
* tests: test xblock endpoint
* test: make all post tests work
* test: check that xblock_handler receives correct args
* refactor: create util mixin for course factories with staff
* refactor: extract course staff authorization tests
* refactor: extract tests to api view testcase class
* test: add get tests
* test: fix tests
* test: fix tests
* test: fix tests
* test: add all crud tests
* fix: refactor to fix tests
* fix: merge conflict
* fix: merge conflict
* fix: tests after merge
* fix: json request decorator
* fix: lint
* fix: lint
* fix: lint
* fix: lint
* fix: new test files
* fix: lint
* fix: lint and apply PR suggestions
* fix: lint
* fix: lint
* fix: lint
* fix: lint
* fix: lint
* fix: lint