[Feature Request] Add support for sandboxing for CROWNBuild tasks

[tvoigtlaender]

The compilation of the CROWN executables in the current workflow relies on having the same software setup on the submission machine as in the remotely executing worker. While the general environment is set through the LCG stack, the overall OS is still an issue.
This is also the reason for why CROWN is only compatible with certain OS.

It would greatly enhance the flexibility of the setup if the local compilation was also performed in the same apptainer/docker container as the remote execution. This would decrease the number of containers that have to be maintained and allow any system that can run apptainer/docker to act as a submission node (The reliance on LCG-stacks in general is also an open point for discussion).

LAW already has a feature called sandboxing that does exactly what is described above, running local tasks in a container, similar to how law tasks are run on a remote worker.

[jhvoss]

In a special case the compilation time can reach multiple hours. In this case it would be helpful to have the option of submitting the compilation itself on a batch system.