Previously, the same runner could be used multiple times with different submissions simultaneously. This, however, yielded errors, for example when one submission time oud (causing the running to be deleted) while another submission was still executed.
Admin actions, such as the shell, can be still executed regardless of any other code execution.
Fixes CODEOCEAN-HG
FixesopenHPI/poseidon#423
When a file cannot be retrieved any longer, we send a redirect to the previous locations. As we usually enable a different render host, Rails sees this redirect as a redirect to another host (from the render host to the main CodeOcean host).
* Remove `send_stream` method pulled in before upgrading Rails
* Remove spring, it is no longer included by default for new apps
* Remove deprecated options from environments
* Remove old asset paths and workarounds no longer needed
* Remove unnecessary `OAUTH_10_SUPPORT` const, LTI still uses OAuth 1.0
* Dump schema with new defaults (and specify precision for timestamps where needed)
