Allow dc_sim to run in staging

dc_sim relies on the `RunAt{Start/End}OfCollect.sh` scripts to trigger processing. This limits dc_sim to only be usable in the live zocalo environment, unless a beamline has been set to use staging, which would only typically happen for on beamline testing. It would be useful to be able to run dc_sim against the staging instance of zocalo to be able to test new features easily. To do this, any calls to the scripts should be replaced by direct invocations of the mimas recipe in the environment that dc_sim is running in.