Rewrite setup-meta-modules extension

[climbfuji]

Is your feature request related to a problem? Please describe.

See #1257 for a concrete example why this temporary solution, which turned into a three-year-old work horse for spack-stack, needs to be rewritten.

Back in the days when I wrote the extension, we had just started on spack and didn't know that much about it. Also, spack three years ago and much fewer capabilities than today. On top of that, we tried to mimick existing software stacks (hpc-stack, jedi-stack) as closely as possible with the creation of the meta modules. Further, we wanted to support both tcl and lua modules.

Describe the solution you'd like
Now that we know spack better, and that spack has advanced a lot, we should go back to the drawing board. Let's revisit the assumptions and requirements from three years ago and come up with a new, clean solution that gives us equivalent capabilities.

Additional context
n/a