Ensuring modules can be rebuilt

[ocaisa]

When including software in the EESSI stack, we should not only ensure that the software can be built on the various archs, but also that --module-only returns an identical set of modules as the original installation.

[ocaisa]

This will also allow us to easily perform the sanity checks on different OSes (and help us to avoid issues like #99 )

[ocaisa]

This is something that we could do in our CI since rebuilding the module tree doesn't take too long.

[ocaisa]

--module-only --rebuild could do that for us and will also compare module files (but requires easybuilders/easybuild-framework#3645 in order for the sanity check to run when using this combination)...but because of --robot it won't check any dependencies.

An easy solution is to tell it to build the module tree in a different/temporary path since that will also do all the dependencies. The downside is that you then need to compare the new modules to the old ones in a separate step.