Add sanity check

While admittedly the documentation contained all the details, when installing this on different machines I ran into some issues that a top level script could pick up early:
- wrong spack version (It requires 0.22, I had 0.21*)
- no libtool installed (resulted in blitz failures, missing `lt~obsolete.m4`, which is a link to /usr/share/aclocal/lt~obsolete.m4`
- check that gpg agent is running

I also noticed that some unnecessary(?) packages got compiled by spack, e.g. subversion?

Maybe we could trigger the bootstrap script automatically (or combine this), e.g. if no conda, install conda, if no spack, install spack, check spack version and (not sure what to do if the version is wrong ... install correct version??), ...

Start by reviewing the bootstrap script and the installation flow described in the issue. Define how the process should handle the required Spack version, missing libtool, and the GPG agent, then verify that these checks occur before the existing failures and that unnecessary Spack packages are addressed.

Written by the indexing model from the issue text.