Detect incompatible K / Python installations

[Baltoli]

When K is installed via kup, care needs to be taken to make sure that we use a Nix-supplied version of Python to run Pyk applications via the Poetry environment. If this is not the case, we see errors like:

• Unable to run kllvm integration tests pyk#357
• kup installs an incompatible version of K kup#82

I have proposed a new feature in kup that will supply the correct Python interpreter path to use; we should also have Pyk print a friendlier error message when the following conditions are met on running llvm-kompile to build a runtime Python binding module:

• llvm-kompile is somewhere under /nix/store/...
• The --python argument (i.e. the current executing Python interpreter) is not under /nix/store/...
• llvm-kompile fails to run successfully

If these conditions are met, we should add a message that suggests running something like:

$ poetry env use --no-cache $(k-which-python)

Note that these conditions are just a heuristic for a particular common bug with kup + K + Pyk, so we should still report the full error message from llvm-kompile, and allow it to run successfully if it somehow does work.

Blocked on kup support in: runtimeverification/kup#92

[Baltoli]

There's a second way that this can manifest, whereby an ImportError is thrown when running module_from_spec(spec). We should catch this and report the error similarly.

[Baltoli]

We should just add this to the new Pyk documentation with some examples of the error and how to fix it.