Explore integration of bwrap for enhanced protections

[jmfernandez]

Some ill written workflows can go astray, and they could try writing outside the expected sandbox, overwriting some input or writing in some input or workflow directory.

bwrap is a low level command line tool which is used by FlatPak and other tools. It uses both linux cgroups and namespaces to be able to create a sandbox where the running program is constrained.

The ultimate target is that every command run by WfExS-backend is run in their corresponding bubblewrapped sandbox, starting with the workflow engine and container materialisation commands.